Never dealt with him personally but have heard positive things about him. The average price of a CB GTP is between $500 and $700. There are some animals with exceptional bloodlines and appearance that can put the price into the thousands. There are also those who think because others can fetch thousands, they should price theirs in that range and expect to get it even though the animal is far from exceptional (no different than with ball pythons I guess).
Typically, animals priced in the $200-$400 range are farm bred or imports that have not been established. If you are not experienced with working with these animals, I suggest avoiding these and spending the extra money for a quality CB animal. Farm bred animals, often sold as CB, are not always established feeders and getting young GTP's to feed can be a challenge.
If you are looking for a quality CB animal at a reasonable price, I suggest checking out
www.signalherp.com.
Bart