Air shocks?

this is my first post so im sorry if I do something wrong

I recently acquired a 1973 dart sport, it came with rear air shocks. The right one is toast. It badly leaks and needs to be replaced.
I don't know much about shocks so that's why im here. Im wondering if I should replace the old ones with new ones? or should I try to convert them back to the original coil springs? Im trying to restore this on a budget since im in High school and don't have much money after purchasing the car, so keep that in mind when replying

Thanks for the help
Zach