As with so many things in life, you get what you pay for.
No money and nothing might get you some volunteers who happen to have some time to kill or may want to support your charity. No guarantee as to standard.
Free entry (to a paying event) may get you some freeloaders who will feel obligated to do some juggling, but they'd like to enjoy the event too.
Free entry and free food will generally get some jugglers who will be happy because they are being fed, so they'll juggle for longer and more conspicuously.
Money: now you start to get service. Again, that cardinal rule applies - you get what you pay for. We can put you in touch with a range of talents, from starving students who'll mess about for a while for a tenner through to professionals who will put on a slick show at professional rates.
You might want a workshop, where we teach rather than perform. Rates vary according to how many people, how many workshops, travel costs and so on.
In the first instance, contact Rupert (Elfic the Jester) on 01803 868053. (Website: www.elfic.org.uk