I agree that if you pay somebody to do everything for you, and absolutely must have a specific brand and model of sight at any cost...it ain't gonna be cheap.
But there are lots of folks with boxes and boxes of old assorted sights, bases, screws, etc. just waiting to be pillaged for a project like this. It's also been pretty easy to find something that "looks like it'll work..." on various tables at local gun shows. And if you have a drill press and some experience and practice, drilling 4 holes, running a tap into them and mounting a simple set of sights is not exactly brain surgery. To me, the scary part of this is the fact that a T3 Lite has a pretty small muzzle diameter, so it's definitely a matter of go slow and measure 10x before you cut once.
I've done this exact job on at least a dozen rifles. I only ran through into the bore once!

And that was a on a .22lr bolt gun, which I still have and which still shoots the same little bughole groups it did before it got a superfluous gas port halfway along its length. Good thing, too; I'd be too embarrassed to try selling it and having to explain it...