PALO ALTO, California — Clients should know – and no doubt some have already found out – that those bargain airfares advertised for low-cost carriers aren’t always such a great deal.

A study by refund.me, the passenger rights service provider, broke down the costs to offer a side-by-side comparison and infographic highlighting how hidden charges boost ticket prices for basic add-ons like in-flight meals, seats and luggage allowances.

An overview of the extra costs of the UK and EU’s major airlines is here: refund.me/flight-extra-costs/

Refund.me took the example of a family (two adults and two children aged 2-11) travelling from New York to London Aug. 11-18 for a vacation.  The price for the family to fly British Airways’ Economy Class totalled $4099.10 including taxes and service charges. Included were: airport, online, and mobile check-in; seat selection free at airport and from 24 hours before departure; three-course meal and drinks in-flight, including alcohol; pre-bookable children’s meals; and baggage (one per person at 23 kg).

The base fare for same date flights with Norwegian, the third largest low-cost carrier in Europe, including tax, was $3651.20. Then the add-ons: seat reservation $45 per person, per direction; one checked bag 20 kg per person, $45 per direction; and in-flight meals $45 per person per direction.

Add-ons boost the ticket price to $4731.20. That’s $632.10 more than British Airways. Norwegian does offer a discount when booking seats, baggage and meals online simultaneously. With discount the final price is $4371.20 – still $272.10 more expensive than British Airways.

“Low-cost airlines have attention-grabbing headline prices that seem an obvious money-saving choice. What budget airlines don’t always show is how these prices are not always what they seem due to ‘price deconstructing’ to appear lower,” said the company.