I grow in rubbermaid bins (19 gallon). The lids make excellent drip trays! For 1 gallon pots, I use the plastic containers that ready-made pies from the local grocery store come in. Small pots, well, I use the clear plastic holders that cookies come in! (My kids occasionally buy pies and cookies- I don't usually buy junk food- but I won't waste a perfectly good drip tray by tossing it out as trash!)
Pie tins and roasting tins. The Reynolds-type throw-away shit. Left overs from cooking/baking. Clean Em up, and slide Em under my smarties.