HI Joe,
Welcome 5 Star. One STRONG word of caution I have for you is to thoroughly research the reputation, support and up-time of a host before you promote them. People's businesses DEPEND on their host and if you give someone a sales pitch about how great this host is and it turns out to be one of the many BAD hosts out there, you can ruin your reputation and do your visitors a dis-service. Even some of the big name hosts are bad.
Do your research at
Web Hosting Talk after you find an affiliate program you think you want to promote and be sure it's a good host.
The other warning is the hosting is VERY competitive so not a good place to start if you are a newbie and don't already have lots of targeted traffic.
As far as commission, it's all over the board. There are some hosts that pay 50 - 100 even on a 7.95 a month hosting plan because if they have good customer stick rates they know the lifetime value of a customer is 300 or whatever. But yes some only pay on dedicated servers too. So you just really have to wade through.
To be totally honest with you - I could sell a TON of hosting. If there was a host I trusted enough to put my reputation on the line for, that I was sure had good tracking and good payouts, I'd be promoting hosting. I'm still looking and have not found a hosting company I'm comfortable recommending.