Most affordable tank?

your local fire station has the cheapest tanks.

thats where i get mine.

walk in and ask if they have any tanks they want to get rid of,
ive got them all for $50 or less,sometimes free.
plus they will fill the tanks also.

just tales a little legwork to find ones that have some/or want to part with some.

dont expect a tank at the first place you try,
but getting a couple tanks for next to nothing is completely worth the effort (y)
 
Firestation auction sale, if my memory serves me well I paid about $120 for a four full setup (with masks, lines, metal tank holders, all those I just throw away).

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