A food scale is fine, as far as I can tell that's what the ones sold by reptile supply companies are. Look for at least one gram resolution, or finer if you want very precise weights.
Got a lil one from Target for $5, not super precise but will do, my girls are 40g, 25g, and 15g,it goes by 10's but once I start breeding I will get a better one, I just wanna know my babies are healthy and ready to breed
Yeah I found a pocket scale on ebay that ranges from .1-500 grams and goes by is to .1. It was 10 bucks. Even though it is a little small I put a Nintendo DS an it and tare it and place the leo on it. It works very well.