Last weekend I discovered the most offensive fee yet that airlines are sticking to customers: seat selection fees. Now some airlines are charging you to select your seat in advance!

Spirit Airlines is charging $15 for a window seat, $10 for an aisle and even $5 for the dreaded middle seat. Canadian Airline WestJet will tack on $10, Air Canada’s Tango class will add $15-$22 and AirTran will run you $6 to select any of the above. Meanwhile, Icelandair won’t allow you to choose seats in advance at all if you book their lowest fares. If you choose not to pay, the airline will assign you whatever is left when you check in, but you should expect the worst seats and to be separated from any travel companions.

My advice is to figure out what fees an airline is going to charge before you purchase tickets and decide if their “lower” fare is in fact better than that of an airline not charging all these fees. Personally, I’m going to fly the airlines that aren’t so fee happy as much as I can. Continental, Delta and Jetblue are still checking passengers first bags for free and offering regular seat assignments at no charge, at least for now!