Are ebay bucks taxable under income?
I wouldn't think so. That feels more like a promotional discount (like a coupon). You can't sell them, transfer them, or even use unless you're spending even more money through eBay. Taxing eBay bucks would be like taxing the use of the coupons they print out for you at the grocery store register - those are only "worth" something if you're in the store buying more goods later, at a slightly lower promotional rate.