Affiliate Programs for Merchants

[LazyCarrot]

Does anyone out there have any recommendations for a decent affiliate program?
The comparison websites all seem to view it from the 'affiliates' perspective - just wondered if anyone had any experiences to share from the merchants point of view...

Preferably looking for a 'no set-up fee' provider, happy to pay a percentage on results of course, but not willing to fork out upfront! but would be interested to hear views on any and all!