FRANK...never sold the 1st brick yet. The way I understand it, Brick Collectors just swap with each other...but if some scarce & desirable brick was to come along, I guess they'd make monetary offers....I wouldn't have the slightest idea how to price any brick.
RAZOR...I imagine if you were to set up at flea markets or have a yard sale, you could sell single bricks....the serious collectors usually only want a single example of a brick for their collection, though they also may purchase more than one of an example as a trader.
Someone wanting to make a patio or walkway may be looking for multiple examples of the same brick....
Me...I don't care if they're the same or not...I think assorted types/names/textures/colorations make for a nice contrast.
try contacting the IBCA INTERNATIONAL BRICK COLLECTORS ASSOCIATION. my father has been a member for about 15 years. it is an interesting group of people who have 4 or 5 swap meets per year. we hosted one at my fathers house several years back. dad has 3 or 4 thousand bricks from all over the world. this group of people have tried to keep this hobby free ,meaning they would preffer to trade bricks rather than sell them. i have noticed that a few pop up on ebay from time to time, but very few will ever realize high dollar because most are very common. if anyone is interested in this organization let me know and i will get you some contacts!!!