IMHO, a lower is a lower. Personally I steer clear of billet lowers and go mil-spec forged. I'm a big fan of aero precision personally as far as lowers go. BCM makes a solid lower as well. Id steel clear of colt or wilson combat, they left extra material in the receiver to make it difficult to install an auto sear. It can interfered with some aftermarket triggers as I found out the hard way.
Lower $100
Lower parts kit $50
Buffer tube assembly $70
Pistol grip $25
That leaves about 200 for a trigger, once you figure tax, shipping and all that.
For a trigger you could go mil-spec or enhanced for around $50, add in a JP spring kit for about $11 and you have a fairly nice mil-spec trigger.
Or you can go fancy, lots of options. the LARUE MBT2 for around $115 is a great trigger, you can catch them on sale for $100.
If you have "a little over" You might look at the AR-gold trigger, comes in about $250. It is an absolutely amazing trigger, it hurt to pay that much, but it was 100% worth it. Light, crisp, short pull, almost non existent reset.
Rise armament also makes a fantastic trigger, friend has one and its pretty close to as good as the ar-gold
Elftman makes a really nice trigger too.
IMHO the geissele is a rugged reliable duty trigger, but your paying a lot for a name, and it is not nearly as good as some of the other triggers listed.
really depends on what you want and what kind of shooting you plan to do with it.
Ok, Aero lowers are currently on sale through Midway usa, for 49.99
https://www.midwayusa.com/product/1022704650?pid=654062