what company is offering $20 a pop?
There really are a ton of companies that are willing to offer $20 for conversions. Heck, I have seen numerous companies willing to give $200+ for each conversion, but just because they offer a lot of money for each conversion doesn't mean it's worth promoting.
Usually, the more money a company is willing to pay you per conversion, the more information and pages a user has to fill out. And the more information and pages a user has to fill out, the less likely they are going to do it.
Stuff like this is called CPA, or "Cost per Acquisition". In other words, if the end-user performs a specific kind of action (fills out a form, calls a number, etc.), you get paid.
If you really want to be successful at it, you really need to analyze the company's credibility and conversion rates, which is not something they will always give you. You'll need to check the conversion rates on both the banners and the landing pages that the users are taken to. The best way to learn about these things is to join a CPA network, as many of them will at least provide a clickthrough rate for banners. The rest you will probably have to test and track on your own.