I'm looking to grab several lpks without triggers (or grips if that brings down the cost).  Where are they cheapest with adequate quality?

I've used Red Barn Armory's custom LPKs in the past:  http://www.redbarnarmory.com/Build-Your-Own-Custom-AR15-Lower-Parts-Kit-LPK-p/rbacustomar15lpk.htm

There might be other options out there, but they have a very convenient way for you to get just the basics with a couple specific pieces of your choice.

Tom's Tactical - $39.95 w/ Free Shipping.  There are also options to ditch the A2 grip and/or the trigger guard for additional savings.  

http://www.tomstactical.com/toms-tactical-ar-15-lower-parts-kit-no-trigger-group

Anyone ever use a Joe Bob LPK?  $30 without FCG...

White oak. Great quality.

Picked up this from AIM just the other day.  No grip, no trigger and hammer. 30 bucks.

http://www.aimsurplus.com/product.aspx?item=XANLPKMHT&name=Anderson+%22Vitals+Only%22+Lower+Receiver+Parts+Kit&groupid=2361

I just came across these guys and decided to give it a try. I can't verify their claims for quality yet as mine are due to arrive tomorrow but it's worth a look. Here is some info from their site. They say they make everything themselves in Texas.

CNC Machine parts, NO MIM. or PCM parts (NO metal injected mold or powder compaction molding)
All major components are Phos+ coated for durability & protection against adverse conditions.
All trigger contact points are Polished so there is little to no creep, clean crisp break with little pre-travel.
All metal parts go through a 2nd machining process, deburring for a clean & smooth finish.
All materials & bar stock are from the highest quality metals: Trigger & hammer 8620 steel, trigger pin 4140 steel, disconnector 4340 steel, bolt catch 4340 steel.
100% Mil-Spec fit & function with higher then Mil-Spec processes & finish.
For 5.56, .223 and 300 BLK.
Designed, post manufacturing & packaged in Texas.

Here's a link to the complete kit but they also offer them without trigger and grip. Cost without trigger and grip is $34 I think. I can post pics once I get mine in hand if anyone is interested.
http://shop-wickedindustries-us.3dcartstores.com/Wicked-Industries-Lower-Parts-Kit-LPK-Complete-31-pieces-polished_p_30.html

I recently used CMMG's "Gun Builder" lpk, available through many vendors.  Top quality small parts.  No grip, fire control group or trigger guard.  Just what you need and nothing more.  Typically in the $40-$45 price range, sometimes a bit lower

Anyone tried the ALG LPK?  As good as their triggers?

Absolutely G2G... building up one of the Aero Multicam sets from a few months ago. Everything fits as it should, and the ACT trigger included is money.

ETA: I bought the LPK with the trigger - LPK is available without the trigger as well

I just ordered 2 of the CMC trigger lower parts kit minus FCG and grip from Primary Arms for $24.99. I have no idea if they are any good.

I have used many kits and only had one issue. The bolt catch on a Palmetto State Armory PTAC kit was out of spec and the bolt would not lock back.

I have had good luck with:

Palmetto State Armory Premium
Anderson
CMMG
Spikes

Spikes uses the spiral roll pins so they go in like butter. Some guys seem to have trouble with roll pins. I personally have no issues with any.

Check out your local LGS and custom builders.  I needed a pivot pin spring after losing one somewhere in my kitchen while building my first rifle.  I ordered a couple of new ones from Brownells but was impatient waiting and dropped by a custom builders shop.  He didnt have any loose ones so he sold me a complete LPK without FCG and grip for $20.  I put the one spring I needed into the rifle and when I got the shipment from Brownells I had a complete kit again which went into build #2.  Always good to have an extra laying around but al extra parts seem to grow into another build.  Be careful, BRD is all consuming!

BRD, no cure, no cure.  Only treatment one round at a time.