Checking change isn't for everyone, but if you enjoy the thrill of the hunt, it can be rewarding. Go to a rural bank and ask for rolls of half dollars - you'd be surprised how many silver halves are still out there. And a silver half dollar today has about $3 worth of silver, so that's a pretty good profit. What you don't want to keep, cash back in at the bank. The only investment is time.
A guy I know who REALLY knows his coins recently found a 1983 cent that is worth $5,000 if not more. It looks exactly like every other normal 1983 cent. The only difference is it weighs 0.6 grams more than it should. He has weighed countless 1983 cents hoping to find a "good" one. And he finally did. So if you find any cent dated 1983 or after that weighs 3.1 grams, you've hit the jackpot. There are only 4 known to exist so far, though.
DeathBUA, the nickels with some silver content were made from mid-1942 through 1945.