Team 228 had two scales donated to us in 2004 from BMS; one was a 150 lb scale and the other was a 400 lb scale. The 150 lb has higher precision, but we normally use the 400 lb since we've found that a lot of students like to stand on them to see how much they weigh.
I've found the same models on McMaster: 17295T31 and 17295T39.
They are a lot cheaper than the other models, if you don't mind the +/- 0.2 or +/-0.5 lb increments respectively.