You can make really good commissions from the eBay partner but it depends on the products which you decide to promote. Interestingly the commission levels vary according to where you are in the world not just on the products you decide to promote. One of the great reasons to sign up is that you can earn DOUBLE commissions in your first three months. They offer free to use link generators, ad creatives and widgets for you to promote different eBay items. eBay has over 162 Million active buyers which means there is a great potential to convert your traffic.
Some advertisers offer multi-tier programs that distribute commission into a hierarchical referral network of sign-ups and sub-partners. In practical terms, publisher "A" signs up to the program with an advertiser and gets rewarded for the agreed activity conducted by a referred visitor. If publisher "A" attracts publishers "B" and "C" to sign up for the same program using his sign-up code, all future activities performed by publishers "B" and "C" will result in additional commission (at a lower rate) for publisher "A".