Flexible seating for my 3rd grade classroom!

I have been using flexible seating for a few years with students that have attention issues. I have noticed that when any student uses the yoga balls or the seat cushions provided by the special education dept. the room is "bouncing" but they are actively engaged. Unfortunately the alternative seating is just for IEP students and if that child needs their tool then the other students can't use it. I have parents that have donated yoga balls but without legs they aren't always safe. I have researched other flexible seating choices and would like to get wobbly stools and luv chicken cushions, as well as stand up desks, etc. I would also like to be able to get yoga ball seats with legs. These all cost money that is not in the regular ed budget. I certainly spend my own money but just need a little help as most of the items are pricey!