Assuming you were to use IRG, given their fees, exchange, tax and shipping, based on my math, the complete LMT MARS-L lower (which also has fully ambi controls) came out to be the same, if not a bit cheaper. That was factoring in all necessary parts without a fancy trigger. The LMT also comes with a SOPMOD stock which, love it or hate it, is a pricey piece of kit.
Now, if you were looking to complete a build yourself, then that's a different storry.