Dallas Craigslist has several of them

http://dallas.craigslist.org/search/tls?query=anvil&srchType=A&minAsk=&maxAsk=

Use this link:

http://abana.org/affiliates/affiliate_list.shtml#t

to find out where the local blacksmith meetings [Hammer In] are. There are often tools for sale out of the backs of pickup trucks to be had for better prices than the gougers on eBay & Craigslist. Ask around at the meeting, and You may find more stuff that they will part with.

Posting on these forums may help too:

http://www.anvilfire.com/hammerin/

http://www.forgemagic.com/

http://www.farwestforge.com/

http://www.iforgeiron.com/

With regard to anvil size, 50-60 x the weight of the hammer is a good rule of thumb. 150#+ is good for anything You will swing with one hand. If You will be using a sledge hammer, look for something 300-400#

Here is another alternative, a lot of work, probably not cost effective, but a project to be sure:

Patrick Nowak - patrickwnowak@gmail.com Wed 04 Jan 2012 23:28:04 #0
Fabricated Anvil

I just finished a very long term project of making a large double horned anvil in the English style. This anvil was inspired by some shown on Bruce Wilcock's website as well as by one that I saw at Quad State a few years ago. I started with two pieces of 4.25" thick plate 16" wide. These were cut to the profile I wanted on a programmable flame table. A third piece, 1" thick, was cut to a similar profile, but slightly smaller. This was sandwiched between the two thick plates and the gap was filled with weld all the way around the perimeter of the anvil. A piece of 1.5" plate was cut for the base. The feet were built up from small bits of scrap welded in place and ground to shape. The horns were profiled by hand with a torch and then ground to shape. Once all the shaping was done, the face and top of the square horn were hard faced with Hobart Hardalloy 58. That alone took about 35# of rod and 12-15 hours of welding and grinding. The hardy holes are both 1.5" square. These were done by drilling and counter boring holes through the face which exit the anvil just in front of the waist. A coworker cut two inserts from 1.5" plate using a water jet. These fit in the counter bores and were welded in place prior to hard facing. The inserts were 3" in diameter. Overall dimensions (in inches) are as follows:

Length: 52 9/16
Face: 91/2 x 19 5/8
Square horn: 17" long. 6" wide at widest
Round Horn: 16" long
Base: 15 3/4 x 19 3/4
Height: 17 13/16
Hardy Holes: 1.5" square centered 2" from each end of the face.
Weight: 1050#

I need to be sure and thank Keane Pardiso and Andy Svaboda who both helped with this project. Keane provided the programmable torch, heavy welders used to do the main assembly and the radial arm drill used to drill and counter bore the holes for the hardy inserts. Andy provided the burners used to preheat the anvil prior to hard facing.
I don't have an exact count of the hours going into this project but I wouldn't be a bit surprised if its close to 100. In the last week alone I've put in about 30. The cost is tough to pin down as I was able to get the steel for less than scrap prices and the hard facing rod and other filler rods and grinding consumables were picked up cheap off of Ebay and from sales at the local welding shop. Actual cost on the project is probably close to $1000, but would have easily doubled or even tripled that if I'd had to buy the material, welding supplies and grinding consumables at new/standard prices. I doubt that this method of making an anvil would be cost effective for any of the standard anvil patterns available new or used unless you are comparing this to the cost of purchasing a one of a kind collector type anvil or having an anvil custom cast and consider your own time to be of no monetary value.

I've put a series of photos in the Patrick Nowak folder showing the anvil at various stages after I got it home from Keane's shop. Photo 4 shows the anvil and burners set up for preheating prior to hard facing. The anvil was actually completely wrapped in Kaowool during the heat process and after hard facing was complete the Kaowool was replaced. The anvil was still too hot to touch more than 12 hours later. Picture 2 shows my two youngest children playing on the anvil. It is included here to show the scale of the anvil. Surprisingly, this anvil rings as loud as any I've ever run across.

Patrick

You can see photos here, but they load slowly. http://www.forgemagic.com/bsgview.php?cat=R