The equipment can be a bit of an investment to start with, mostly 'cuz there's a good bit of it. Goggles, fins, BCD, regulator, tank, weights, dive comp, and an emergency backup air tank at a minimum, plus wetsuit or drysuit as the local climate demands.
I don't even want to try and guess what they'll be charging for these after Orange Monday, but the dive comp, BCD, and regulator are the pricey bits that I wouldn't recommend trying to get a good deal for by buying used.