is amazon ads associates legit?

i want to make money by advertising amazon on my tumblr, is it legit though? am i going to get scammed? am i actually going to make money?

It's legit. How much you make depends what you advertise and how much your tumblr audience is willing to buy through your site. Unless you have a very large audience with significant disposable income, you're not likely to make huge amounts off any affiliate program.