If you are planning to sell merchandise, alcohol, food, or really anything at all, it is a good idea to provide ATMs for your patrons.

For those venues or outdoor sites that don't have permanent ones, renting them is very straightforward. There are many companies, that rent them out these days. Place them close to your merchandise/bar areas for best results.

Point of sale machines are also available for events. These hand held devices process debit and credit cards for purchases. Keep in mind that you'll pay a bit more for these systems and they are likely to slow down your lines. Do your research and find a company that fits into your budget if you are going this route.