At my wits end....2 year old?

i have a little boy who is so hyperactive that it makes getting anything done, including going outside to play in our yard impossible. he doesnt listen, no matter what. a behavioral therapist told me once to give him a piece of candy if he listens (ex he wouldnt sit in his carseat, he would flex and lock his muscles and i literally couldnt physically force him to sit long enough to strap him in). i tried that but it only works for certain things, like telling him if he lies still for a diaper change. he is so extremely strong willed that i feel like crying at least once a day. if i take him outside to play he will continually try to run in the street, run up to neighbors who are outside, try to open others car doors, and scream and cry if i stop him. im 4'11'' and he is a big strong boy. he knows he can tire me out. after only 20 minutes outside i give up and take him in. its embarassing because its obvious to others that i cant control my child. during the day currently my husband takes the car to work so i cant take my son to the park. this is changing somewhat soon, but i feel there needs to be some sort of outlet soon. his doctor says he needs to be in some sort of day program, but after my husband got out of the military he has found employment but we are unsure if we can afford to spend more for daycare than even on rent. IMO he really, really needs to be around other kids at a place where he can get out his energy as he acts better around other kids. has anyone dealt with something like this that could offer some advice?