Does amazon affiliate program matter for a small site?

It can, but go in with low expectations. Commission rates are small in most categories and the cookie only lasts 24 hours, so you only earn if they buy fairly soon after clicking. You also need three qualifying sales in the first 180 days or the account is closed and you have to reapply. Where it works for small sites is very specific buying-guide content, where the reader is already about to buy. If your traffic is mostly informational, display ads or a niche program with better rates usually pays more.