I use 2 types:
1. Office Depot 11 lb postal scale. Nice for most items. Also, I can put a bucket on the scale, zero it out, and then weigh my stuff.
2. Hanging scale. American Weigh H66. I think it weighs up to 50 lbs. or so. I like it a lot for hard to weigh items such as packs, sleeping bags. I also like it for the "final" weigh in. Cost about 26.00
I think both are good to have.