Some photo booth providers include unlimited pictures, while others only include a set number of prints (200). After that, there is an extra fee per picture (for example, 40c). Before making a decision, check to see how they operate. It will vary widely between providers. If the information is not on their website, you'll need to check with them directly. When hiring a provider that includes a set number of prints, you'll need to estimate how many you need ahead of time. As a rule of thumb, count one picture per person. This only needs to be an estimate. Additional pictures can be purchased (or rather added to the bill) on the day of the event.