Stones
You cab find stones at any good shop that sells knives. You could also search ebay and turn up a source. Shipping might be as much as the stone though!
Classes
Have you tried at a gun club that has skeet, trap, Sporting Clays? Our club has a post it board and there are always adds offering instruction. You can meet people there that are great instructors.
Coins
Am not a forum member but have been a collector for years. Are you planning to use it as an investment or just for fun. Most investment money goes into NGC or PCGS certified coins.:):)
Reloading
Single stage is great as long as you have lots of time to invest in it. All of the reloading equipment I have used was bought used and it worked fine. Parts, dies etc. are very easy to get if you stick with MEC, Hornady etc.:)
Had a great time doing this as a kid. Sand the axles smooth by chucking them in a drill and smooth them. Use graphite on them for race day. Make sure the edges of the wheels that ride on the wood are smooth also.
Same thing happens every time there is an incident. Remmember how scarce ammunition was two years ago. Will be used as an excuse to try to change things.
As long as it kept in a cool dry place it will last years. I know guys with shotgun shells that are years old and still work great. If it is damp or chaging temperature (attic) all bets are off.