I've already been through this, so I'll share my work - we're probably not going to the same party anyway. Like the other guy said, it doesn't have to be exact. Really, the only things that are "exact" here are the jacket and the patch, and you could easily fudge the jacket. But it's reasonably priced and it's great for fall weather in my area, so I didn't mind buying it. That's the best part of this costume, everything in it is just clothing, so it's not like you're buying things you can only use once. I've been wearing my Mr Robot jacket around town while I wait for Halloween.
Most of the costume is defined by these three items. In fact they're the only parts of it he wears with near perfect consistency (the hat comes and goes a bit). Note I have no relation to any of these sellers, I just found them from this comment.
Finish it off with the items below, which you probably already have or can easily get locally. Up to you how detailed you follow this, but at a minimum you'll need a plaid button-down, an undershirt, jeans, and black shoes/boots.
If you don't wear glasses, you can finish up the look by finding round tortoiseshell framed sunglasses and popping out the lenses. Aviator-style sunglasses as well. Can probably get them at Target or Wal-Mart for $10-15 each.
Finally, go a day or two without shaving, stand and speak with confidence, and call people "kiddo" a lot.
I don't have a picture of me wearing it, but this is what I've put together. If you want a mask too, this is it. I also got a bunch of fsociety stickers to hand out while wearing it.
I found that pricing on some Mr Robot related items has increased substantially since season 2 started. I managed to get one of the masks at San Diego Comic Con which I was putting together a surprise for my son's birthday next month.
I purchased my patch on eBay and had it sewn on a jacket that I purchased from this site. (pricing has increased $10 since July) I then added a hat from Amazon and a couple of different color scarves I purchased from eBay.
Improvements in 1337 Hax0r skilz are not guaranteed.
A less expensive and closer to what you see on screen option for Mr. Robot's jacket:
Universal Overall Company Eisenhower Patch Pocket Jacket
I prefer this hat to the Alternative Apparel one, which, unlike the one you see on screen, has navy trim:
Otto Caps Washed Solid Pigment Dyed Cotton Twill Brass Buckle Cap - Khaki