ANVILS-2 Buying used anvils
From a post on the Blacksmiths Junkyard 1997.
Used anvils vary in price from 25 cents to 3 dollars a pound. In the 1960's the rule of thumb was $1/lb. Today the market is just crazy. It all depends on who's buying and who's selling. I've been lucky and bought some realy nice anvils at a little less than $1/lb. I've also been given anvils for free (twice!) and have sold anvils for as much as 2.25/lb. New anvils sell for $5 to $6 a pound and there is some question as to the quality sometimes.
The trick is knowing a good anvil from a bad anvil. When buying and using old anvils you have to overlook a lot of little chips and dings. Anvils in good condition don't have cracks or big chunks missing. Good anvils have wrought iron or steel bodies and a hard steel face. Cast iron anvils are junk and not worth the metal it took to make them. A good anvil has quick rebound when struck with a hard hammer. Good anvils ring when struck depending on how they are mounted. An anvil that is clamped or bolted down dosn't ring very well. Small anvils in the 100 lb. range will ring enough to hurt the ears while large anvils in the 300 lb range generally ring less. Taping the horn or heal from the side will make an anvil ring more than when struck on the face. An other wise good anvil rings less or not at all if it is cracked (a hard call).
Modern farriers anvils with the very long horn and heal, narrow waist and arched base are not suitable for general blacksmithing NOR manufacturing horseshoes. They are a light duty device for adjustment and modification of factory made shoes. Many people (including myself) classify small 90-125# American pattern anvils as farriers anvils. The advantage of these small anvils is portability. The London pattern anvil with less horn and heal in the same weight class is OK for light general work. A serious blacksmith will wear out a small anvil in a short time (a year or less). For general work an anvil of 200 lbs or more is needed. Because small 100-130# anvils are very common they sell for less. Bigger anvils generally sell for more per pound due to their rarity.
When is an anvil "worn out?" When the face starts to get sway backed to the point you don't need a straight edge to tell. When the face starts showing a fine pattern of stress cracks. When any part breaks off the anvil without undue abuse (ALL anvils are abused to some degree). It is common on very old anvils with thin steel faces for peices of the face to break off or get worn through.
Broken worn out anvils have their uses and thus have some monetary value. They are better than no anvil at all and generally better than railroad track anvils. At this point the question becomes, "Is this a museum piece?" and "Should I be pounding on a museum piece?" Tough questions that even museum curators fight over.