I have gone to my local welding gas supply house and purchased older (certified tanks) and gotten some great pricing. I have 2 - 20# tanks I picked up for less than $60.00 each and that was filled with gas (1 with beer gas). When the tanks go out of date, the suplier will replace the tank at no charge (unfilled of course). A regulator of course is something you should be looking to purchase new (IMO). You can of course find them used at better than new prices on e-bay/craigslist.