So would I!
Upon the op's suggestion, I did check completed auctions for "depth gauge" in "watersports" going back two weeks. If the "over $200" USD gauge "just" sold it should have shown up. Perhaps it was listed under some obscure description that the op happened upon. Anyway, here are all of the same type models of US Divers depth gauges I found (AFAIK, no one has quantified that any one of the various models of 100', 150' or 200' gauges are any rarer than the others):
200' gauge-
SOLD- $21.62
U.S. Divers Depth-Master I Scuba Diving Gauge Used - eBay (item 230656539973 end time Aug-12-11 10:16:54 PDT)
200' gauge-
SOLD- $13.06
Vintage US Divers Aqua Lung Wrist Depth Gauge Master 1 | eBay
150' gauge -
SOLD- $12.50
AQUA-LUNG US DIVERS DEPTH - MASTER III GAUGE 0-150 FT. | eBay
Now here's one to compare. It's a 100' gauge,
New-In-EXCELLENT-Box, which sold for
$99 with ONE bid in a SEVEN day auction.
Vintage New US Divers Scuba Diving Depth Gauge NIB | eBay
Anyways, Rocklgnd2b, I know I'm coming across as a bit of a pain, but I'm only pointing this out for your own good to save you time and disappointment. Believe me, we vintage divers KNOW for how much those gauges
commonly sell. But, if you really did see one just sell on eBay for over $200, then who am I to say?