You will love guinea-pigs, they are amazing little animals.
I got mine from a rabbit rescue- I phoned in the hope that they might have had some GPs handed in. My DD wanted a boy (so we were looking for 2 boys as neutered boars are harder to find than neutered rabbits).They had 2 'must go as a pair' brothers and the rest,as they say, is history!
Think about online delivery for things like hay.It can be cheaper if you buy bulk. ( I buy from The Range, huge bags of hay.Mine get through a bag a week.They have a deep filled outdoor box in their shed and hay in their indoor cage for night, even though I hate the smell of hay)
There's loads of threads on S.F.A. to plough through for advice. About what they eat,what's toxic, indoor/outdoor guineas.
They might appreciate some cardboard on the paving to insulate them and to chew.They love boxes to hide in.It's their instinct to hide under or in things (they don't burrow like rabbits and they don't climb like little rodents). Ours have a wide,carpet covered ramp to get on top of their hay box, but most of the time they are under the ramp or playing "Haunted Hay".(They scuttle about under cover, you can just follow the movement of the hay, but can't see the GP)
Definately 2 (or more) they need company, especially if they are not in the house .They might squabble a bit but it usually sorts itself out.
And one of the loveliest sights to me is our GP1 in full popcorn flight. (GP2 purrs like a tiger and passes the most toxic gas) Love them really!