If are using this forum you have probably seen that most users wear a signature promoting different services. That is usually a profitable way of promoting and is used by most of the reputed sites that accept crypto. There are some good campaign managers that should be able to give you some advice on how much could it cost and what level of traffic could you expect from you budget. A purely affiliate programme has the advantage of not having risk in your investment and the obvious problem of not getting the best to work for you.