We are having a surprise 90th birthday for my neighbor and would like people to pay their own way, but not to bring a gift. Any nice suggestions on how to word this invitation?
Probably the easiest way would be to have a potluck party and ask people to bring a dish to pass. Asking for money is a little trickier. If it's something where you need money in advance you might ask for a "suggested donation" or something along those lines, and arrange a way for them to pay you. Maybe "party donations preferred instead of gifts". I'd leave it a bit open-ended though so if some guests prefer to bring a gift, or perhaps don't have the money for a donation they won't feel slighted.
Your presence is your present is always popular. If you want people to pay their own way, then you just figure out how much it will cost and state that. We had my parents' anniversary party on a tour boat (2-hour "cruise") and we just said Please join us (with cruise details, time, date). Ticket price: $XY. To order: Call x781-7789 and tell them you are with the Z party.
Perhaps in the invitation you could say it's a "no-host" birthday party at (wherever it's to be held) and the establishment's prices are value, moderate or pricey. Seems odd to me you would do this if other than close family is invited.
If you are hosting the party, then it really is your responsibility to foot the bill. It doesn't need to be elaborate or fancy. If all you can afford is to have homemade coffee, that will be fine, it would be much better than asking the guests to pay.