It largely depends on the quality of the material. Some material is purchased by knappers for making knives, arrowheads, etc. Some material is purchased by rock shops to sell to rockhounds. Apache tears (small, round translucent obsidian pieces found in vermiculite) are sought by lapidaries and collectors alike. There are varieties of obsidian that have sheens (when a new fracture is created they appear to have a reflective quality) of various colors: gold, silver, purple, rainbow and others. There are various colors of obsidian: black, white, mahogany, rainbow, and a combination of two or more of these colors. There is also snowflake obsidian which appears to have "snowflakes" imbedded in the black matrix.
One of the most important factors is the quality of the glass itself. If the material is grainy or shot with holes (bubbles) then it is of low quality and not many people want it except as a specimen to compare to other types.
Each winter in Quartzite, Arizona wholesale and retail rock, gem, and mineral sellers gather to sell to the snowbirds that flock there. It is world famous for its rock/gem/mineral sales and the nearby rock/gem/mineral shows. I'm sure they sell a ton of it there throughout the winter.
So there is a market for obsidian. That market, however, is based on the color and/or sheen, the quality, and the quantity. Most lapidaries and collectors aren't interested in a little tiny piece. They want something they can cut and polish and set as jewelry, make into bookends, or knap. Apache tears would be the exception because they like to tumble them and then make earrings, bracelets, and necklaces with them.
Hope this helped you. HH