I just sold an RRA two stage trigger for $50 to a guy on here a while back. Look in the PX. A LOT of lives have actually depended on this trigger, truth be told. The Larue everyone talks about but Larue did what Larue does and ran me off a while back. The RRA two stage was sort of THE go-to two stage trigger for AR's for a long time. IIRC there's one thing you can do to increase the reliability, you replace the (disconnector pin?) with drill stock cut long enough it won't slide out when installed in the lower.
I have a couple higher end GI triggers if you're interested, you can PM me. I won't be using 'em. LMT mfg. They're around 5-6lbs I think but a little stone work turns 'em into good 4lb triggers, BTDT. PM me if interested, I'll sell one or trade it for something reasonable. Not all GI triggers are the same. Some of these companies park the whole goddamn thing, some "polish" contact points, most leave the contact surface "as is". I'd start with one like that and take a fine stone to it and call it good if you really wanna save money. Maybe fart around with some different springs too. You'll get the 4lb. mark for sure and there are ways to get it lower but I wouldn't recommend it, a smooth 4lb release is better than a crunchy 2lb any day.
Best bang for buck IMO is the Brownell's Geissele triggers, they make two, one is a two stage and one is a rapid fire single stage type trigger. You gotta wait until Brownell's has 'em on sale, then they're about $130 but they're basically on par with the standard Geissele shit. They use a different method of retention (removes a mfg. step I think) and they don't inspect and engrave each part, they do 'em in batches, and that saves money. Given it's only $30 more than an RRA two stage cost twenty years ago, I think they're a great deal.
But I've tried most of the ones available and got to do it side by side. Geissele just wins hands down, they charge that much because they can, hell, they could probably charge more if everyone actually compared 'em prior to purchase. There are companies that charge more than Geissele and don't even come close. The trigger that surprised me the most was the AR Gold, didn't think I'd like it but it's nicer than I thought. The Wilson was the biggest shock, most expensive, least quality.
The $330 KAC trigger is one of the most expensive AR triggers, a really nice reliable and bomb proof looking 2 stage you can depend on, but it's not nearly as nice as a Geissele SSA/E or especially a HI-Speed, which it got swapped with. So with triggers at least, cost isn't the only factor and you don't always get what you pay for here IME.
