Freecycle is a good source of pots; some garden centres have a container for people to leave old ones in if they're not required.
Is there a prize for guessing what this question is about?-perhaps Majorie has hidden pots and grit and we are being asked to find them-like a treasure hunt-who wants to be Anneka?
you can pick up old pots at some garden centers,that's where I get mine or from outside houses who often put things out and people around are often to glad to get rid of plastic pots if they know you require some.
I buy my pots and horticultural grit from the local 'chep' shop. he also sells pots from small up to very large planters. Shop around is the best advice.