Reddit mentions of 2 Kydex Plastic Sheet Black 12" X 12" X 1/16" (0.060")

Just in case anyone would like to make their own, I found everything on Amazon except the screws and nylon belts. Those I just grabbed at Home Depot and Hobby Lobby.

Clips:

Kydex:

There are enough sheets here to make 4 belts. I took a 12x12in sheet and cut it in half for my belt.

You could overnight some Kydex from Amazon and put together a sheath quickly using that. It would be much easier and much quicker than anything you could do with leather, given that you don't have any leather or tools. The link above is showing 2 sheets for $10 and is Amazon Prime (so free 2 day delivery).

While $55 does seem a little high for a magazine release with the amount of engineering, marketing, and production the price is reasonable, especially if you do not want to register.

There is also the Patriot Mag Lock for $45 or the classic Prince50 for $17

Where are you finding grip wraps for $150? a Monsterman Grip is $45
an Exile Machine Hammerhead Grip is $30

If you want a Thordsen FRS-15 or a Hera Arms Featureless Stock Then you will be spending ~$150

Of course you could make your own Kydex grip wrap for $11 plus [hardware] (https://smile.amazon.com/Kydex-Holster-Black-Eyelets-Count/dp/B00NKOX0B4/ref=sr_1_2?ie=UTF8&qid=1483519643&sr=8-2&keywords=kydex) and a heat gun

Make one