Which ones? there are two types of commissions on amazon books: 1. their books which the commission structure is pretty much the same as any other amazon product. 2. books you publish. You get 50% of the sales for those.
The commission on them are very good, you should try them out, they pay the same as any other product on the site.
Commissions start at 4 percent and go up to 8+ percent. But, to get 8 percent comissions you have to sell at lest a thousand + books each month.