From what I've found the average conversion rate of amazon affiliate is 1%.
Amazon affiliate can make you some decent money although the payout is very low.
One great thing about the amazon affiliate program is you can earn money from commissions off of other things people buy on amazon through your affiliate link even if you didn't promote them.
So although the amazon affiliate payout conversions are low and the payout isn't that great it can be a good income generator for you if the person buys more than one product.