Hosting a party away from your house has a lot of benefits but can also create monetary challenges. You doesn't have to worry about cleaning up or having people running through your house, but many places charge an additional fee. If you're visiting a zoo, for example, guests might be responsible for buying their own tickets to the attraction. You need to find a polite way in the invitation to ask your guests to bring money with them.
Call the event or attraction where you're holding the party ahead of time, and ask about any additional fees. For example, if you're holding the party at a professional sporting event, your guests will need to pay for any snacks or drinks they want, even if you buy their tickets.
Ask about discounted rates to the event based on the size of your group. Many places, including amusement parks and zoos, offer discounts, sometimes for groups as small as 10 people. This reduces the amount of money your guests need to spend on their own.
Print the invitations out ahead of time, or buy pre-made invitations. When you ask guests to bring money to the party, do it in a hand-written note on the inside of the invitation or on a separate slip of paper inserted in the invitation.
Tell guests the amount of money they need to bring, while also thanking them for attending. For example, write, "We hope you'll join us for John Doe's birthday at the zoo. Admission price is $X." Add a note informing guests of the regular price and the discount they're receiving, such as "Admission is usually $X, but our group received a discount. Admission is now $Y."
Inform guests if you plan on paying for part of the event. For example, write, "Each guest will receive admission to the park. Please bring additional funds for souvenirs, drinks and snacks during the day." The same also applies if you're throwing a party where guests need tokens to play games and you're paying for a few tokens.