What is best way to make up difference between concrete and drywall in garage

The bottom part of wall in the carport was never covered with drywall. The distance from floor to bottom is around 9-10 inches. The bottom area is concrete blocks. The issue is distance from outer face of wall to outer edge of drywall is 7/8. The thickest drywall is 5/8. I need to make up the additional 1/4 inch. I was going to use 1/4 foam insulation but it is much more expensive than the other foam insulation(1/4-$40+). I had thought of cutting wood pieces to that thickness but was concerned it holding up drywall because it is so thin. Any suggestions? I’ll try to post pic within the hour.