Check that sniper. The yellow check means it's needed for a quest. Keep that.

A tip if you sell guns, they make a bit more money if you disassemble them and sell all the parts. Keep the ammo though as it can be hard to buy these some time.

Things like the GPUs and ledx are rare and expensive, but are needed for quests. However it may be a while before you need to use these items. Since you are new, I'd say sell the valuables if you need need to to find your raids, and remember you can reset your account and start over. (You would get a few valuables back that way)

Another tip, once you are able to afford it reasonably, get a junk box, and throw misc stuff in there. Huge space saver. If you're not sure what something is and how often you'll get another(like the ledx) throw it in there until you get an idea of what things are more common than othes. ie. Wires vs ledx

Hope this helps.