I love the idea of those metal paint cans, I have no clue how much they cost though, something to look into.
I usually buy styrofoam at Michaels or ACMoore, using a coupon. I am always amazed at how expensive it is. I've been saving the chunks of styrofoam from boxes I get. I just bought 3 new light fixtures for the house and saved the styrofoam chunks. But I do love the balls and the precut floral foam cubes.
I hit 2 dollar stores tonight, and did see the sand pails and thought I would buy them, but my bouquets aren't that theme, so I didn't get them, I didn't want to end up changing my ideas to fit the bucket! I'll do a bucket another time w/a beach theme.
I did find a few pencil holders, for desks. They will work great, they're taller and a good size. I'll put a chunk of foam in there, wrapped in tissue paper and be all set for a couple of the bouquets. I've never noticed it there before, but Dollar Tree and another one both had styrofoam and floral foam this time. I was really hoping for some bright colored metal pails but nothing like that at all.