This place saved the day recently when we needed really, really big trash bags. None of the big boxes had them big enough (Home Depot, Lowes, etc.) and the event was hours away.
With a Hail Mary phone call, Maintenancemart saved the day! Not only did they have bags the size we needed, the guy encouraged me to bring in one of my receptacles to test it right there in the store, rather than take any chances. Fortunately, the bag fit. After ringing me up, he even carried the box out to my car for me! The customer service was top notch!
Other cool things:
they have pretty much every cleaning supply you could imagine -- including those super-cool vacuum cleaners you wear like a jet-pack!
there is an enormous plant growing into the rafters -- they'll let you take a snippet if you want to test your green thumb at home.
Helpful tip: the parking lot is NOT the first one you see when traveling south on 7th Ave. turn into the drive right after that... :)