Ah, for the days of $15 10 gal. cornies again!
Shoot, when I started kegging I picked up 3 5-gallon cornies and a 20lb tank for something like $50 or $60 all-in.
And I didn't have to drive far to get it either.
That tank has long since been exchanged, but those cornies are among the cleanest newest looking ones I have.