Q&A for How to Find Silver Half Dollars

Banks really aren't in the business of trading coins. It's not likely they'd want to take the time with you to search through their stock of coins. The other options mentioned above are more likely to be useful, particularly local coin dealers.

Yes, that's usually how people acquire coins.

This wikiHow article on building your own metal detector should have all the information you need.

It is probably worth around $200,000.