Uncut Skill Gem Level 20

How TF I'm supposed to trade for a level 20 skill gem if top 1000 results are scammers?

1) on the right side of the listings “ignore player”, rinse and repeat. The bottom 1000 is not representative of that many different players it’s a hundred plus listings from a few different folks.

2) FAR MORE IMPORTANT: As a general rule items like that, you want to go to the trade filter and set the “exalted orb equivalent” (or whatever scale is appropriate), and filter out “too good to be true” results. For that item for example a minimum of 200 exalted orbs; that you still get 4000 listings tells you this is a fair price people realistically expect, and then the bottom 1000 which as you say are scammers anyway are filtered out.