With planting season upon us, check with your local nursery to see if they give discounts if you bring back the pots and trays that you have at home from previous purchases (if still in good condition).
When I go to garage sales I watch for the 2 gallon and larger black plastic pots that trees and shrubs usually come in, quite often they are "free" at garage sales and then I "return" them for a credit to my local nursery. Our local nursery does not give any kind of credit for smaller pots or trays or the peat pots. The credits given can be used for anything at the nursery. Then when I cash in my credit I feel that I can "splurge" on that special perennial or shrub that I've had my eye on.