Before anything else, perhaps you should determine how you want to earn.
To you want quick bucks?
Or do you want long term gains?
If you want it quick, you could sell the resale rights to your product. I'd say $75 to $300 would be a fair price to charge, depending on the quality of the work. I've seen people succeed with this without even having to create a dedicated website to promote the product. They just do some forum marketing. Of course, you have to market in the right forums. But this much I could tell you... there will always be a lot of interested customers for information products with resale right.
This approach, however, will shorten the market life of your product.
If you want some long term gains that would take some time to gestate, then do all of the things you mentioned in your post. Try ClickBanck! Try PayDotCom! Try your own promotional campaign! Try them all!
Where to start?
Well you need a domain name for your product. If you're selling an eBook entitled "Treating Dogs With Mesothelioma," you could register a domain name that can be associated with such.
Then you have to prepare a REALLLLYYYYY GOOOOODDDD sales copy. You could research about some copywriting techniques or you could hire a professional copywriter to prepare a sales page for you.
Then the usual marketing tactics.
Add some bonuses to your product to pad up its perceived value.
Or make a fire sale, like, offer your product for $20 for 3 days with a warning that the price would increase to $30 after that period, and to $40 after 3 more days, and so on and so forth. This is an effective call to action.
Enroll your product with ClickBank, PayDotCom and other similar unified affiliate sites.
Try article marketing, forum marketing, blogs, search engine optimization and the likes to drive traffic the the page where your sales copy is located.
Strike a deal with eZine editors so that they may recommend your eBook in their mailing list.
There are a gazillion more things you could do! The info on how you could do them are scattered all over the net, and all over this forum.
Keep us updated, ok?