Just noticed that Fry's had a balance capable of 0.01 g accuracy for $10 if you get their ads. http://images.frys.com/art/email/021917_sun285btg/sun_web_pop.html?site=emailconfirmation
If you are buying coins on Ebay and other places you need a good scale with 0.01 accuracy to weigh the coins you buy. It's the first line of defense to check for fake coins.
My scale goes to 0.001 gms which ensures that I get at least 0.01 accuracy. BUT As scales go it wasn't cheap; around $100 if I recall correctly.
If you don't need to weigh many silver dollar size coins or gems, this is a very accurate 20 grams X.001 scale. I didn't believe it for the price, under $20 , but bought one and took it to the lab where we have some calibrated balances and weights. The scale only deviated from the a recently calibrated Mettler x .0001 balance no more than .0002 grams. https://www.amazon.com/dp/B00ESHDGOI/ref=psdc_678508011_t2_B0012TDNAM
I guess I'll throw in a plug for the scale I have here: https://www.amazon.com/gp/product/B012IJCI1Y/ It measures to the nearest 0.001g, and has a weight limit of 50g. I paid $29 for it. It's currently available for $32 with free shipping. This scale will weigh dollar-size coins, and 1oz bullion coins (actually anything up to 1.6 troy oz.) It's very repeatable, as well. I would say the accuracy is somewhere in the 2-3mg range. I use it to weigh ancients primarily.
