(Original post by ghostbusterbunny)
Not particularly. It's expensive to start out with piggies as obviously you need to pay for the cage/accessories etc.
At minimum a 120cm cage for a pair. Something like this
is ideal (and at the moment very reasonably priced). Pet shops will tell you a 100 cage (or smaller) is suitable for a pair, but trust me; the extra space is necessary and you'll get much more out of piggies if they have the space to be guinea pigs.
Two is fine, they need company so I'd either have two, or 4+ (not a trio as you get one left out). But if you're starting out, definitely two!
Totally up to you. Boys can smell a bit more than girls; but I actually find boys to be friendlier than girls.
They are nappers, they don't 'sleep' like a hamster - so they will be active at all times depending on when they nap.
Generally no, but they soon learn to link sounds with food and will wheek at you when they want food - like this
If you mean out of the cage, they can but not on their own. They will chew things as they investigate things with their mouths. If you want to let them out of the cage I would suggest a playpen with walls and a fleece blankie to catch any 'accidents'.
I have had 36 guinea pigs, not one of them has bitten me. You've got to severely irk a guinea pig for it to bite. They are not like hamsters that are easily tamed, but they will, on the whole, happily sit for cuddles and will start coming up to you in time. Taming a guinea pig is a long process - they are naturally prey animals and WILL run away from you; some guinea pigs never stop doing that.
I covered the cuddling, but the exploring - depends on the pig! I've got one girl that won't sit still and is always on the go but most of my pigs will sit still!
I would recommend a rescue above a pet shop all the time. By going rescue you know you're getting healthy, sexed, non-pregnant piggies - I've got 15 pigs from the same rescue and all of them have been absolutely perfect for me! However, if you choose to go to a pet shop, you're looking at anything from £10-22 per pig; depending on where you go.
Guinea pig pellets/muesli (I would always recommend pellets); hay (should make up 80% of their diet) and fruit/vegetables (I can give you a list if you want).
Hope that helps!