My 21st was really different! My mum worked for a local heritage centre, and they had an old bus they used as a free pick-up around the area for holidaymakers wanting to visit it. It had been in the old St Trinian's films - so, really old! They let my mum borrow it, and the driver, and we took all of my friends to Freshwater West - a local beach off the beaten track and famous for its huge sand dunes. We had a barbecue and a picnic, had races up and down the dunes and messed about on the beach. One of my mum's friends brought some champagne and we could all have a drink (poor driver!!) but the most memorable bit was when it broke down on the way home! It had overheated, and we used the empty bottles to fill up the radiator with water from a river we'd stopped next to. All in all, a memorable day!!
You could all chip in for a minibus, and then do something less expensive? That could be your only expense - a picnic doesn't have to be much, and beaches are free....have fun, happy birthday!! xx