Home Depot stores will cut plywood to fit into your car, but will often charge after the 3rd cut. Typically, after the 3rd cut, they will charge $0.50 for each additional cut.
But some stores may not do more than 3 cuts because the store may have a store level policy to not do project cuts. The cuts they make are using saws that will make rough cuts with old/ dull blades (using rough cut blades), so they may not be smooth cuts. The main reason for them cutting wood/plywood is so that it will fit into your car, not to make all the necessary smooth cuts to finish your project.