Don't know, skgolfer. I bought a new '95 model for $8450 plus $2400 for the front end loader and in '99 the dealer bought it back for $8000 with just under 500 hours. Belly mowers are pretty expensive and that's sure low hours for a '96 model.
Assuming that it is in excellent condition (it should be with only 150 hours), I would guess it to be worth between $6000 to $8000 depending on several factors such as what part of the country you live in. This is based upon prices I saw about 2 years ago while shopping to upgrade my older B7100.
I will note, however, that since the introduction of the "10" series (B2710/B2910, etc) and the "BX" series, I have seen a B2400 and a larger B2150 (both 24hp/mid-mower/turf tires/hydro/4wd/under 500 hours/ps...) sit on the local dealer lot for a long time with an asking price of $9900. I would've jumped on that price a while back.
Bottom Line: Although I don't have enough data to confirm it, it appears that the market for the older used "B-series" Kubotas (which used to have a very high resale value) has declined somewhat since the introduction of the new "B-xx10" and "BX" series.
Two years ago I bought a 1995 B7100 HST for just under $8,000 from the original owner. Equipped with the 60" mid-mounted mower and less than 200 hours on the clock. I though it was a pretty good price at the time, especially after looking at a new 1999 B7300 (same basic tractor, only newer model) with the same mower deck for more than $11,000, plus 6% sales tax. I would guess anything in the $7,000 to $8,000 range, assuming the tractor's in good shape, would be a fair price.
The B7100 HST is a great little workhorse. I'd buy it again in a heartbeat. The only downside, if there is one, is that the B7100 doesn't have power steering. Even then, the only time I ever notice the lack of power steering is when trying to turn at a dead stop.
We have a friend/neighbor with a B7100. I'm not sure how much the loader holds, I guess around 450-500 pounds? Anyway, the steering gets "noticeable" with a load, but not unmanageable... Still, it made us go for the B7500 with P.S. /w3tcompact/icons/smile.gif