These are super folks who will answer all your questions with grace and style. They handle all the get-started details and make it easy to wade through the related documents. Unless you hold things up, they will have you up and running within a matter of days. You'll find the rates with Authorize. Net quite reasonable.
Many merchant services charge much more.
Com - Takes you to a page on CNet. I wandered about the Basic Plans section. As with other sites doing this sort of thing, the list is not complete in any sense. There is a nice option at the end to select from the set per your criteria. I never have the time to read it, but every week I say I'll take a quick peek, then end up reading the whole thing.