I've heard good and bad about such deals. Usually the bad ones are posted on the internet somewhere so difficult to believe. My next door neighbor swears by Craigslist. Espeacially the free stuff. He went and picked up a refregerator, a stove, sheets of boards, many other things for free. He sold cars, campers via that same list and never a problem.
As to those coins and currency. I know nothing about currency values but those coins appear to be just normal, nothing special coins. I wouldn't do it but you never know you may find something of value. Not much to loose since your getting pretty much close to face value.