Where can I find a merchant account with reasonable prices for an adult site?

Try doing a yahoo or a google search for one..

IKEA and walmart.com,,

Your business falls into the highest risk category for credit card processing. You don’t have to go through a third party processor though. If you Google “adult credit card processing”, you will come up with a whole bunch of potential processors and the first in the list is appropriately called.

Be advised that the reason not every merchant account provider can accommodate your business requirements is that US banks will not underwrite certain very high-risk accounts (like yours). So companies that can provide you with merchant services are large enough to be able to underwrite (in other words to assume the risk) themselves. Most of the time they also have relationships with offshore banks and will be able to do your international processing as well.

It is hard to tell what the best pricing would be but I would expect it to be over 4% per transaction.