First and foremost, there are basically 2 major types of Meerschaum pipes. One made from Block Meerschaum, and ones made from compressed meerschaum clay or bits and pieces off the "good stuff" they pulverize and them compress. Simply stay away from compressed. You can tell because it will state proudly in the description that it was made from block. They generally, and conveniently leave off on the others that they were not made from block.
Assuming you are buying a Meerschaum from Block you will be buying a pipe that will last for years if properly cared for. The major price differences in Block pipes is who carved them. Like briar, the better carvers command high prices deservedly. I have sever Meerschaum pipes, all from block, one is a plain brandy and was relatively cheap IIRC about $150.00. the others go up from there.
If you want to see some beauties just use the search bar and look up meerschaum and where it says by, put in Chasing Embers. They are too skull-y for my taste, but they are absolutely gorgeous!
Good luck in your hunt!