Ok I don't think you all need to tell this person to rescue! rolleyes Yes it is a rescue forum but don't over load the OP!
I'm not sure of any good pet shops,
some Jollyes stores are good but never pets at home! :{ My guinea pigs were from a pet shop but I got them for my 9th birthday (I was responsible at that age and was animal crazy! Still am now- I'm 14

) I didn't really know about rescue centres at that age, just knew I was lucky enough to be getting some baby piggies. x)
If I was to get guinea pigs now though, I would go to a rescue centre because I have learnt about how many are sadly neglected and need loving new homes. However, I'm glad I didn't go to a rescue before I got mine because I wouldn't have my 2 lovely girls! x)