You can buy a semi complete LPK for like $50. I think its from CMMG. All mill spec parts but does not include any trigger parts. So you can get your own. I went with a CMC drop in trigger... nice setup and not expensive. Keep in mind, the semi complete (no trigger) LPK's DONT include a grip or grip screw... but some grips do come with their own. Otherwise, I wouldn't buy any high end LPK. From what I can tell, they are all very much the same.
You'll need to get a buffer/tube/spring/nut/endplate and stock. Keep this in mind. You can sometimes find a kit that includes all of it for a good deal, or you can buy the parts individually. Sometimes the parts are cheaper individually and if you want to buy an upgraded stock (like a magpul or something) you wont need the stock that comes in the complete kit. Im pretty sure I saw just the tube/nut/endplate at oneshottactical...
You'll want to check weather or not the upper you buy comes with a dust cover and forward assist or not. Most of the ones I've purchased did, but the last one (aero precision from Irunguns) didnt... I didnt think of it and they were the only parts missing at the end of my build.
If your going to buy an upgraded rail system, check to see if it comes with a barrel nut. If it does, you don't need one. If your going with a plastic fore end you'll need a barrel nut and delta ring.
Your better to buy a complete bolt carrier group with bolt than piece that part together. Charge handle is up to you.
What you need to decide is just how custom you want your gun. Make a list of the parts you WANT to put on it... all the upgrade stuff. Then figure out what other parts you need to finish it off. If grips/stock/handguards are something you want to buy higher end, you can figure out what parts THEY come with and only buy the rest of the stuff you need.
Check out
http://ctcsupplies.ca They have some great deals on build part package deals. They usually have the small parts you might need and they carry some of the lower cost brands of LPK's.
