You don't need a LLC, you can just enter into a partnership and be done with it. The thing an LLC gives you, however, is some liability protection as well as tax benefits.
As for bank, that is going to depend on how much money you have in the bank at any given time. When I opened my account for my business I had ~$1000. That made me look into local banks, since bigger banks like Chase required at least $1500 in the account at all times.
