Nare, you need to have actual sales on Amazon before you get any earnings. I believe that with Ebay you get some income for clicks, but I have never used Ebay apart from very briefly on one hub.
As for why people aren’t buying off Amazon from your hubs, I wish I knew as I have yet to have my first Amazon sale, and I’ve been on HubPages nearly a year. Someone told me that it took a year for him to get his first sale and then after that he has one every month. So it will happen!