Are you wanting to build from parts (ie you can pick and choose parts kits, triggers, stock, to match your requirements/budget) or looking to buy preassembled (generally going to be more expensive for equivalent components if someone else builds it for you)?
I've built a couple of 308AR lowers and several AR15 lowers, not too hard if you choose that route (and I'm a medic!
Hemostats are actually in my tool kit, real handy for holding roll pins and the front takedown pin detent.)
You can also buy preassembled and swap out components as budget allows.