@greene33 Makers mark would help, a Hay Budden is typically worth more than a Vulcan, for example. It sounds like it’s quite a far way away (100 miles) but when you are in that area I would snap some photos.
The most important part that really determines price is condition - are the edges crisp or chipped? Rounded is ok, and preferred, but good edges on an anvil come at a premium. Is there swayback (a dip in the middle of the anvil) when looking at it from the side? Put a level or straight piece of wood length wise on the anvil. If there is no “dips”, it comes at a better price.
Typically, these days, you can fetch at least $3 per lb unless it’s in poor shape. If you have an anvil that is in very good condition (flat, no dips/divots, clean edges) and of good make then you can get up to $5-6 per lb.
Ball bearing drop tests are good for show, but if it’s a good maker then it becomes pointless. A good hay budden will always have good rebound, for example. The ball bearing test just shows it’s good steel.