Quartzslab, a Great Britain crystal maker that was selling by the piece crystals for ham gear, was bought out by Klove in Belgium.  I do not know their prices,  Quartzslab prices were in the range ICM charged with a minimum order, or pay minimum order price for one crystal which was around $55.  Here is a link to Klove's HC6U holder size.  Guessing you would have to email them to get a quote. 

Charlie, W4MEC in NC