There are lots of good cheap ones on amazon. I've been eyeing a smaller scale for traveling. But as mentioned, look in the kitchen section of any department type store, you likely to find one there. I personally look for one that weighs down to 1 gram, weighs up to at least 2.5-3 lbs, and has a bowl or allows for a bowl to be attached easily.
As for the comment on what is an average weight... to be honest I don't tell people what an average weight for a hedgehog is anymore.... or try to avoid it. Hedgehogs come in so many different sizes... I seem to be a magnet for big hedgehogs. I just calculated the weight for the hedgehogs I have cared for over the years. The average for weights is over 550grams. That number is only that low because it includes 2 that were under 300 grams at their healthy weights.