One thing, you may have to search a little. My local Wal-Mart had them in the aisle where all the packaging supplies and tape was, but it was on an unmarked, bottom shelf, in a plain white box with the blank side of the box facing the aisle. If I hadn't pulled it out to see what it was, I'd never have found it.
I bought a digital scale, measures to 2000g by 1g increments. while I use it occasionally for measuring rockets & parts, mostly I use it for accurately mixing small amounts of epoxy. it's paid for itself many times over. I use it many times every day.
Sunday we used it for a pinewood derby, weighing in the cars. I use it for other stuff too.
great tool, I don't regret spending the $$$. I think it was around $60.
I think one consideration before buying a scale is what other uses can it serve around the house other than just rocketry stuff.
I bought a digital postal scale that weighs up to 10 lbs. in ounces or grams. I at first just bought it to weigh rockets, nose weight, simulated weight for motors ect..
I have since found it to be useful in other areas.
It has been used in the kitchen to measure certain ingrediants.
My dog recently had puppies so we started a growth chart based on daily weighings.
This scale can also download the lasted shipping charges for the major shippers. So now when I want to sell something on ebay I can easily include shipping charges.
Yea it was $100 but as much as it now gets used it was worth it.
Another type of scale that can be useful for rockets can be found in the fishing department of Wally World or similar stores. These fishing scales are electronic, and I have found them in several different versions. The lightest duty one that I have found would weigh up to 15 lbs, and the heaviest duty one I have found would weigh up to 50 lbs. These have a handle on top and a hook on the bottom (duh... they're designed to weigh fish, go figure). The digital displays are large and easy to read, and they weigh in pounds and ounces. Fairly cheap, too. I think I paid around $20 or $25 for the 15 pound one that I bought. I have found the hook very handy for weighing rockets that use launch lugs. For larger rockets or ones with rail buttons, I use a sling made out of rope to cradle the rocket. These work really well. If you happen to enjoy fishing as another hobby, they can serve double duty.