I have found the best way to get started is to use your local. bank. Go ask the teller that you see the most. They should be more than happy to accommodate you if you have an account there and have been banking with them for awhile. If you have formed a friendly relationship with one of the tellers even better. One of the tellers at my bank I see often, was in my high school class. We weren’t friends or anything but that connection was enough to get started. I explained what I was doing. She was actually excited To know, because there is someone else in the area who coin roll hunts. But she didn’t know what that was. She just thought it was weird when this guy would show up and ask for 1,000 dollars in coin rolls. Now she knows. So now it’s even at the point where we exchanged numbers. Any time some old person comes in with a bunch of rolls to deposit. She puts them aside and calls me. You can also find out when the bank re-ups on their own change supply. And either get first dibs or I tag on 500 or 1,000 extra into their standing order. Everybody says half dollars are the best, but I have had luck in dimes as well. If you get serious with it, you will have to call around to multiple banks in your area and start doing “runs” makes for a good winter hobby when the ground is frozen.
Good luck.