it's free around here, i get about 75-80 pounds of WW every time i look, maybe i'll toss the mechanic 5-10$ if he has a big buckets worth, but most are still glad to give it away as long as it is not a chain store. i end up with about 10-15% of that being iron and zinc. but unless you live in NY or CALI, you really dont need to pay, just do some footwork.
my method is have a wire clipper, if you can crimp the weight it's lead, if you can't.....it's not. after you do it for a couple days you'll be able to tell the difference pretty easily just by looking on 90% of them.