I'm getting it no matter what because I'm sick of working on a 25 pound railroad baseplate, but how's this look? http://hudsonvalley.craigslist.org/for/2436465176.html The guy says it's #120 and I'm paying him $240 for it. Seems like a pretty good deal to me. Fishers are good anvils, right? I'm bringing a scale with to make sure it really is #120.

Looks pretty good. Yes, Fishers are good anvils. I don't think you'll have any complaints.

The one edge I can see looks a bit rough, but nothing that can't be worked around or even (carefully) ground out, eventually. Looks like the face is intact, and in decent shape. Horn looks good, too. I don't think you'll regret buying it at that price. You are going to be stunned at what a difference it makes in your ability to move metal, compared to a flat, thin anvil that puts no mass under the hammer (i.e., what you've been using up to now).

Follow-up question: What's a good way to secure that anvil to a big stump?

Yep, Fishers are very good anvils. You will be happy with the purchase.

Follow-up question: What's a good way to secure that anvil to a big stump?

I like to make spikes about 5/16" rod (1/4" will work too) and drive them in as far as they will go and then cut off and bend the end over the anvil foot. Basically ending with 8 hooks holding the anvil. Staples tend to bend too much and often end up not driving in far enough to hold properly.

Funny my stapes were forged from 3/8" stock and they didn't seem to bend badly Do you find that 3/8" bends worse than 5/16" in general? If so you can forge your staples from 1/2" (smile).

(now for real fun my largest anvil is held in place with regular commercial fence wire staples---but not over the legs; just a few pounded in along the side curve and the front and back edge---it's a 515# Fisher and so doesn't jump around and just a little hint is enough to keep it in place. Of course without them it did slowly drift a bit over the course of a year.)