LFAR’s aren’t AR-15’s. It’s easy to find AR-15 receivers for $50, high quality carrier assemblies under $100 - that just doesn’t happen for LFAR’s. Handguards are also typically slightly more expensive, you’ll even often see upcharges on barrels. It’s easy to spend $50-100 more each on a handful of parts in LFAR’s such AR-15 pricepoints simply aren’t meaningful when considering AR-10/LR308’s.
Yes - gunsmithing and selling custom AR’s paid a lot of bills for me for several years. I build a dozen or so each year still. In general, I have told folks for the last ~10yrs, if you really want a proper AR-15, budget around $1000 and you’ll never be surprised. For an LFAR, I recommend $1500, with $1800 as a contingency - and frankly, it’s still easy to go well over that.
Excluding these silly “builds” where a guy buys a complete upper and complete lower and pins it together for $50 less than the complete rifle, building a low end, Mil-spec-ish AR carbine very rarely saves any money. Outside of panics, it’s typically possible to buy a Mil-spec-ish carbine for $250-450, and at those times, building them only comes at a savings if you depreciate your tool costs over a handful of builds.
As reference for a higher end spectrum, I built an AR-15 and an M5 LFAR for myself finishing both last year. They were not completely identical in componentry, but shared many common parts plus similar component quality standards. Even with considerable dealer/gunsmith discounts and sale pricing on everything else, I have $1900 before optics into the AR-15 and $2500 into the M5. No extravagance and no aesthetic cost-adders, no billet, no cerakote, no TiN or NiB, just proper builds for PRS competition - only spending extra where extra spent makes a difference. My AR-15 price is even bloated a bit, as the non-SAAMI wildcat barrel had a slight upcharge and the handguard cost a bit more than a true equivalent (not available) to the handguard used on my M5. So the price gap between these two should have been at least $100 more. Not uncommon to see a $300-800 mark up for similar rifles, just scaling from AR-15 to LFAR.