pls help me price pair of 120 steel hp tanks

I have a bunch of scuba equipment I've decided to sell. It's about
time, I haven't dived for about 6 years. Everything I've got should be
in great shape, I treated it well when I used it and I've stored it
well since then.

I wrote to a few local scuba shops to get an idea of their interest
and 1st responses indicated that the strongest interest was in my
steel tanks.

I have both a pair of 80s and a pair of 120s. All described similarly:
used with air (not nitrox), DIN valves, low usage, minimal scratches,
last inspection good thru 11/96, DOT-E9791-3500-TP5250 7-94.

I'd like opinions on fair market price for these tanks so that I can
arrive at an asking price. Of course, 80s and 120s would be priced
separately. Anyone?

Thanks in advance.