In my state,IL, I'm only asked to show an ID if the total amount of metal I bring in is more than $100. I once asked what this was for and the guy told me it had nothing to do with the IRS, rather the state of IL feels that $100 is the "line in the sand" that a person would feel is worth stealing metal to sell. Plus my driver's license doesn't have my SS#, of course the state could look it up but it would be troublesome. In addition, I'm not given a receipt unless I want one. The yard guy once asked me if I wanted a receipt and I replied that unless I could buy something with the yellow piece of paper(receipt) the same way I buy something with the green piece of paper(money) he can keep it. Since I do this primarily as a "paid hobby", going to the yard once a week and make $30-$60 each time I go, I end up putting a close estimate on my taxes.