Welcome.
Can't say much more than what has been said.
Rescue's are your best bet at healthy, correctly sexed, well bonded pairs.
Also, as mentioned please include vet bills into your original funding, unfortunately people don't take this into account and their animals suffer. Vet treatment is expensive, so please consider ALL aspects of guinea pig care before you get your piggies.
They are better housed inside in a minimum cage of 120cm for a pair or a 2x4 c&c cage.
However more space is better.
Exercise is needed, so a run for floor time would be a good investment.
Personally I feel Grainless food is better, but everyone has a different opinion.
Diet should be 90% hay.
A rescue will help you with all necessary advice when you go to them, they are extremely helpful.
&& kudos for doing research first!