I opened my account with Fidelity because they offer no free Roth IRAs. There are enough banks that offer $0 minimums, so I wouldn't worry about $500 or so.
You can check out a full table of
Roth IRA Accounts by bank on this page.
It's got 12+ on the list so far. You'd be surprised by how many banks charge ridiculous maintenance fees when the competition does exactly the opposite.
Good luck with your investing!