Thanks mle292 for the faboo link.
I can actually buy these at a hardware store that's a block from my house. I'm thinking that I'll be making fair use of their services. $25 for the big bag, plus $95 to collect it after it's full, with no time limit between getting it and picking it up.
Dumpstering is actually one of the uglier issues. Paying rental on a dumpster, only having it for a short period (like seven days), permit for a street-load dumpster... it adds up. This is cheaper and more convinent.