TradeDoubler
They are European based and have a large list of merchants, many travel-related and also a large selection of others. Their merchants include: Air France, Avis Car Hire, Opodo, Boots, Dell, Curry’s, and loads more, from condoms to golf breaks to cameras.
They pay regularly and are reliable. The only downside is a little quirk where every merchant has to approve your application to promote them, so it can be easy to lose the impetus while your account is pending approroval. Despite this - highly recommended.
