, that one's tough! I never purchase wool in ounces! The imperial system is a nightmare for me, but I tried a conversion website, and it gives me 200g = about 7 oz, that's the weight of a medium sized handbag, like this one
A bead doesn't weigh much though, it won't even make a difference on my letter scale!
When I first started buying wool, I liked assorted packs with a lot of different colors in it. I got some off ebay (can't remember the seller's ID), and I think outback fibers makes sampler packs as well now. And I got a bunch of natural (white) wool that I dye myself, so that I have more freedom with the color choices.
Off course I'd recommend you check local farms as well. Personally I really prefer buying from local and smaller businesses where I know the sheeps are treated well.
Also, go for merino or corriedale, or similar fine wools because they felt much faster than coarse wools. Wool that's too white might not felt well because of the harsh treatments it goes through since it's necessarily bleached. Not to mention that's it's not eco-friendly.
I like to know what kind of dyes the farmer uses on the wool as well, and I really try to go for organic/plant dyes as well, but again, that's an issue I'm pretty concerned about but I don't want to sound like I'm lecturing