I have a few customers who buy several sets of PCBs to allow them to sell kits or fully assembled versions of my projects.
It only seems fair that I reward them for their continued support, so in future buying 10 sets of PCBs will enable a 10% discount. If you really want to go big, then buying 20 sets will double the discount to 20%.
Additionally, if you are in the UK spending £100 or more will enable free postage.