Depends on your product some. You might also look into MySpace advertising-- it's wicked easy to try out in their beta ad manager, but I find that the CPC is pretty high for toying around with at first.
StumbleUpon seems to be a good one for interesting/clever sites in terms of conversions, and the effective CPC is around $0.05.
With Adwords, there's some fun things digging through and finding keywords your competitors aren't really looking at. There's also a lot of people overlooking keywords in unconventional ordering of the words.
StumbleUpon seems to be a good one for interesting/clever sites in terms of conversions, and the effective CPC is around $0.05.
With Adwords, there's some fun things digging through and finding keywords your competitors aren't really looking at. There's also a lot of people overlooking keywords in unconventional ordering of the words.