The 308 is so forgiving with so many powders it's hard to pick just one. I would suggest a couple of powders to get you going but if price is a major consideration then accuracy is not a prime objective. The reason i'm saying this is , in order to find a powder your rifle likes you will have to try a few and that is when your costs rise, and nothing says that your rifle will like that bullet either. Here are a few of the classic 308 powders:
IMR4895
IMR4064
WW748
BLC2
IMR3031
H380
Varget
There are others like VihtaVouori and my personal favorite since discovering it AA2520, the list is endless. For cost savings look at the WW748 they are usually a little cheaper.
bigbull