I used customsawing.com for a few years. This will probably be the first time in a few years I haven't placed an order with them. Before I found them, I was going to go broke buying calls for my sons. Angus is 10, but he's a fairly accomplished caller. A couple of years ago, I went in his room to tell him to turn down the calling tape and it was just him. Even watching the closeout sales at the end of season wasn't feeding the habit efficiently.
I made slate calls and glass calls for myself and my sons. It was just a great way to make a call that sounded good without a whole lot of cost. I think I spent $50 and made a bunch pot calls with various strikers. From there, I started experimenting with odd materials, both as surface material and as strikers. All my projects were crude looking, but I was working to produce sounds not art. Somewhere along the way, I experimented with copper and that was how I ended hooking up with Brian Warner's Heirloom Turkey Calls .
Copper has a unique sound, and some mornings it's just the ticket.
Brian has a product called the "Copperhead."
It is an inexpensive way to add a copper calling surface to a friction call-- either a box or a pot call. He was running down somewhat the same lines I was, but he's also a real artist-- gorgeous calls. Now my call making has taken a back seat and Angus and I are field testing for Brian.
I found that making my own calls went a long way to teaching me another level of subtlety to the calling. It certainly got me thinking more about friction over mouth calls. I'd recommend customsawing to anyone who wants to take calling a step farther.