it depends, have you ever weighed the bud you have now with a scale? if so, just try to remember how much of the bottom of the bag it filled up. if not, it's hard to tell.
Just look around here in this section for people posting 1/4's or 1/8's and remember thats what it looks like.
here is what you can do. super stoney mcguyver but here it goes: 1 plastic cup thats durable and not flimsy 1 small saucer or bowl that can fit in the cup fill the cup with water about 1/2 way. set the mini saucer on the suface of the water. the little bowl should also be plastic so it will float and not be heavy or it will sink and your bud will be wet.so it needs a high lip even a shot glass will work cuz the bottom is heavy but it will still float. then after the little thing is in the water, mark the water level on the side of the cup so you know thats the tare line basically then if you have something that is a known weight like a 1 gram calibrator weight, then mark that on the side of the cup after the water level rises. the weight could be anywhere from 2 to 4 bucks im sure, but you may as well get a hanging handscale for that price. but hey its fun physics
an 1/8 (if in a sandwich bag) should slide off your fingers (both hands facing inwards, pointer fingers extended and touching, rest of fingers in a fist) rather slowly at first but then fall. make sure to give the bud some work to do, aka have it pretty high/close to the fingers so it has some sliding to do, not like on the edge of a cliff haha so hard to explain, but so simple... hopefully you can understand? in my experience though this is a pretty legit system for being rather ghetto. if its ~3.4+ it'll usually slide, if not it just hovers there. very intense experience.. lol.
i just feel it in my hands. i ball it up and put it in my fist. for me a quarter is my whole hand, so i just go from there when i get some. try to remember how it feels in your hand when you buy a good sized sack.
Man your hands must be kinda small... Or mine are big Really after you buy for a month or 2 you will basically know what it looks like.
A nickel weighs half of a gram. Much cheaper than a calibrator weight. You can also make a balance scale. Here are plans for a pretty elaborate one. A Home-made Balance Scale
This is fucking Genious man. I will rep you after my 24 hour wait. A penny weighs 2 grams, so I am sure you could only spend a couple CENTS to do this
Just make a balance with two cup-like containers of equal weight, and a pencil or some rod to connect them with. You can balance it on your finger or something, and look up online the weights for common things like coins to scale out your weed. It's what I did before I bought a good scale.