I have come across a friend with a used Garret T04Z twin scroll turbo laying around on one of his shelves. Now it's on the shelf for a reason , it is missing the reverse threaded nut that retains the compressor impeller. It also has slightly moderate wear on the fins but still usable. My question is how much should I offer my friend? Any input will be greatly appreciated and helpful to me.

Assuming its a garret and not a Chinese knock off. I would think 300 bucks would be a pretty decent offer. It depends on how proud he is of it and how much he wants to sell. You have to gauge that and adjust your price accordingly. Keep in mind the turbo may need an entire rebuild(which can easily cost upwards of 500 dollars), and unless you just go through it and do it before you install you may be pulling it back off to rebuild it. So don't get in too deep.

Thanks alot for your input. Two brains (literally haha) are better than one. He asked me what was my first thought , I told him honestly at first I was thinking $300 but after doing some research I thought it wasn't worth anything and my offer was $0. He looked at me like I was crazy , paused for a second and said, "100 bucks its yours". Woohoo score! I'll post some pics when I remember how.

Yah, not a bad idea on the offer honestly. Until you know what your working with. If you take it apart and are able to get it fixed cheap. Then If I were in your shoes wouldn't have to think too hard about throwing him some extra money.

Haha yeah that would be nice but after I buy either a $699 doc or $1499 full-race T4 Twin scroll manifold , $300+ 45mm turbosmart hypergate Wastegate and a $300 downpipe , I don't think there will be any left over. Not to mention fueling upgrades (oops I did). My current setup can safely support 460whp. Yeah he'll understand.