I think that would depend on the TPG slab. Also which coin is being sampled. Most likely what a collector is willing to pay for it.
eBay sales are your best option (for those that have sold recently). Also, David Schwager wrote a book which has good info. https://sites.google.com/site/sampleslabbook/
Here are some sites for some help. http://samplecoinslabs.com/index.html/ http://coinauctionshelp.com/forum/index.php/phpBB3/index.php And this is Davids site and he has a book on samples. https://sites.google.com/site/sampleslabbook/ And the original site of Cameron Keifer at sample slabs for info. http://sampleslabs.com/ David is keeping track of prices paid and all samples out there as they are discovered.
