How to add a checked bag without overpaying

The hold bag is usually the largest variable on a cheap ticket, and on every airline flying from Sofia and Bucharest it is at its cheapest in the first booking.

That makes the order of decisions matter more than the shopping. Decide how many bags the trip needs, price them on each candidate fare, then compare the totals. A fare that wins on the seat and loses on the luggage is not the cheaper fare.

The multiplier is what catches people. Every Ryanair and Wizz Air bag fee is charged per passenger, per one-way flight, per bag. Ryanair labels its 20 kg row as a charge per item per flight. Wizz Air's own fee data records the same method on all four of its checked tiers. Bulgaria Air prices its published table one-way too.

So one bag on a family return is rarely one charge. It is usually eight.

This is the clearest evidence in the whole subject, because Ryanair prints it in two columns rather than leaving you to infer it.

Per passenger per one-way flight: a 10 kg hold bag is €10.49 to €44.99 at booking and €24 to €75 afterwards. A 20 kg bag is €21.49 to €59.99 at booking and €39.99 to €75 afterwards. A 23 kg bag, capped at one per passenger, is €28.99 to €80.99 at booking and €54 to €97 afterwards.

At the bottom of each band, waiting costs between 60 and 129 per cent more.

That is a price structure the airline publishes, not a claim about drip pricing, which makes it the strongest reason to buy at booking anywhere in this pillar.

You can take up to three 20 kg bags per passenger, and only one 23 kg bag. If you need more than 20 kg, price that 23 kg bag against a pair rather than assuming two smaller ones win: at €28.99 to €80.99 it undercuts a 10 kg and a 20 kg bag bought together at both ends of the band.

The rule always buy it online has a published exception, and it is worth knowing because it arrives exactly when you have already made the mistake.

Ryanair charges a flat €35.99 at the airport bag-drop desk for a 10 kg checked bag, while the online price for adding that same bag after booking runs as high as €75. So if you missed the booking window and the app quotes more than €35.99, the desk is the cheaper counter.

The conditions are narrow. It is the 10 kg tier only. It is the bag-drop desk, never the boarding gate, which is a separate and far more expensive place to solve this. And it only works if you arrive early enough to use the desk.

The 20 kg tier has a flat desk price too, €59.99, but that sits at the top of its own online band rather than below it. The exception really is one tier wide.

Wizz Air works differently and the difference changes what you can plan for.

Its fee schedule splits by where you buy, online or call centre against the airport, and by season. There is no published row at all for adding a bag after booking. So on Wizz Air, waiting does not trigger a known surcharge. It exposes you to dynamic drift of unknown size on a price the airline says depends on the travel date, the purchase channel and the bag weight.

What is published, and large, is the airport price. A checked bag bought at the airport is €70 to €80, against €20 to €25 at the published online floor. Roughly triple, per passenger and per one-way flight.

Buy at booking as the default. Just do not repeat the Ryanair logic here, because the Wizz Air saving is real and unquantifiable rather than printed in a second column.

Wizz Air sells four hold-bag tiers and the gaps between them are small. The penalty for outgrowing the one you bought is not.

Bought online, the tiers start at €15 for 10 kg, €20 for 20 kg, €26 for 26 kg and €32 for 32 kg in low season, and €20, €25, €31 and €37 in high season. So the step from 20 kg to 26 kg is around €6.

Going over the tier you bought costs €13 to €15 per kilogram, charged per item per flight at the airport. Wizz Air states it plainly: weigh your bags before you arrive, because that surcharge applies to a bag sitting between two tiers.

Five kilos over a 20 kg tier is therefore worth more than the next tier up, several times over. If your bag is likely to land near a boundary, buy the tier above it. Only one 10 kg bag is allowed per passenger; the heavier tiers are not capped that way.

Among the carriers flying these routes, Bulgaria Air is the one where you can know the exact figure before you open a booking flow.

On an international route, the first checked bag of up to 23 kg and 158 cm is €50 prepaid and €70 at the airport, one way per passenger. The second is €70 prepaid and €100 at the airport. The third is €120 prepaid and €150.

Prepaid covers buying online at booking, through Manage Booking afterwards, at a Bulgaria Air office or through an agency, and the window closes three hours before departure. After that only the airport price applies.

So waiting costs a known €20 per bag per direction, about 40 per cent, which is one of the few penalties in this pillar you can state as a single number.

Note the second-bag step. Two prepaid bags one way is €120, not €100, so the cheap answer is usually fewer heavier bags.

Aegean's fare ladder is the one most likely to sell you a bag you did not get.

Light includes no checked baggage. Flex, despite the name, also includes none: what it adds is date-change flexibility and a second cabin piece. Only ComfortFlex includes a checked bag, one piece up to 23 kg. And the Family fare includes no bag either. Its benefit is a 50 per cent discount on a bag bought afterwards, measured against Light-fare pricing.

Aegean publishes no fixed price for adding a bag. Its own page says the fee depends on the fare family, the destination and the dates, and sends you to a calculator. Third-party sources report roughly €13 to €60 online and roughly €25 to €70 at the airport, and they disagree with each other, so treat both as estimates rather than prices.

Buying through the call centre after ticketing adds €8 per passenger on top, and pre-purchased baggage is non-refundable.

This is the arithmetic that decides whether an included-bag fare is an upsell or a saving.

Two adults and two children flying Bucharest to Milan and back, one hold bag each, is eight chargeable bag events. Not four, and certainly not one.

On Ryanair, eight 20 kg bags bought at booking is somewhere between about €172 and about €480, depending where on the published band your dates land. On Bulgaria Air, eight prepaid international bags at €50 is €400 exactly, because that table is fixed.

Set those totals beside the fare difference to a ticket that includes a bag. On Bulgaria Air the threshold is exactly €100 a head, being one prepaid bag in each direction, so a fare with luggage included is the cheaper ticket whenever it sits under that.

That comparison is invisible on a search results page. It has to be done deliberately, and it only takes a minute.

Ryanair allows passengers on the same booking who have checked bags to split their combined weight however they like. Two 20 kg bags can travel as 15 kg and 25 kg. The only hard limit is 32 kg for any single piece.

For a family that is a real saving and most people do not know it exists. Four travellers rarely need four suitcases. Two heavier shared bags across four people is two bag events per direction instead of four, and the packing is easier at both ends.

The ceiling is firm elsewhere too. Wizz Air also caps a single piece at 32 kg and states that carriage will be refused above it, and it allows up to six checked bags per passenger of which only the first three can be paid for online. The rest are bought at the airport, at airport prices.

So the cheapest family answer is usually fewer, fuller bags rather than one each.

Everything above assumes the bag is bought before you leave home, because the alternative is the most expensive version of the same trip.

Carry a Ryanair checked bag to the boarding gate instead of the bag desk and it costs €46 to €75 to load it. Buy a Wizz Air hold bag at the airport and it is €70 to €80. Bulgaria Air's airport price for the first international bag is €70.

Those are per bag and per one-way flight, so a family that improvises at check-in can pay more in fees than in fares.

It is a common outcome rather than an unlucky one. A European consumer study found that about a third of all baggage charges were levied at check-in or the boarding gate, averaging around €45.

The fix is unglamorous. Decide the bags with the dates, buy them in the same session, and weigh them at home the night before.