Generally, how do you find out what a particular niche will pay without having a full site setup. What are some good ideas that will give me a rough estimate? Thanks!
See what advertisers are paying for keywords in Adwords: https://adwords.google.com/select/TrafficEstimatorSandbox For keyword suggestions for a primary keyword, go here: https://adwords.google.com/select/KeywordToolExternal The cost for advertisers in the adword traffic estimator are for ads appearing on Google search, not in Adsense ads. But it should give you a rough idea of what pays and what does not pay much.
In addition to checking what advertisers pay, setup a free blog with Blogger, and try it out until you get about 10 clicks so you have a rough estimate what you get paid before you decide to jump into the niche and invest money.
ax3l: Exactly what I had in mind doing, thanks will do that momentarily. Anyone know how much I'll actually get off each click?
The amount you get paid is determined by how much advertisers are willing to spend outside of Google search. I've seen as much as 90%, but normally it is much lower. Every now and then you might get an Adwords noob that sets bids wrong and you get very high paying clicks, but this is rare anymore. Your traffic quality matters as well. Search the forums, and I'm sure you will find a lot of details about earnings per click.