perceptionreality - yes guinea-pigs are lovely little creatures but as guineapiglet says do read all the GP related threads (yes there are hundreds of them and some subjects do come up repeatedly but well worth spending a few happy GP related hours before you get them)
Cage: as big as you can. I've got a 4'x2' and my boars are very
even though it's only for winter bedtime.
I've never tried C&C but you can customise them to suit (and add to them)
GPs aren't really athletic so if you do have two levels they might not bother with the ramp.
But I'd have to challenge Astelia on the 10cm climb. One of my GPs when I was a child could run upstairs- literally sprinted up 13 steps without batting an eyelid. Another GP would climb downstairs. And these were fully grown adults 
If you go to a rescue , you'll know you'll be giving two pigs a good home and be more likely to definately get 2 girls (unless you get very young ones, it's hard to tell when they are babies). I've had 2 sows that weren't...result- baby piglets surprise .
Bedding- I use cardboard, newspaper and hay. All easy to dispose. They love a few boxes to hide in, tunnels.
I gave my boys a box with a fleece to sleep in and a pile of hay .They slept in the hay
, totally ignored the fleece.
Fleece is a nightmare to get the hay off. Shavings and sawdust can irritate their eyes and respiratory systems.Shavings can dry their feet and fur.
There's loads of food threads (some things are toxic or unsuitable for hogs.Some things they should only have 1-2 times a week)
You'll be told what dry food they're eating and given a supply.If you want to change it, you can mix the two types over a period of time.
I use Burgess Excell. Easy to get hold of.(about £10 for 4kg bag. They're meant to have 50g /hog/day ) so it last a while.
I do tend to overdo the hay for my boys. They play in it , hide in it, eat it, nest in it- so of course pee/pooh in it. (So alot of waste)
But the way I see it, I pay £3.90 for 4kg hay + same for soft barley straw. A full bed (half a bag of hay + half a bag of straw) lasts 3 days or so (hay need replenished more .Indoor bed changed daily because they are messy little boars).
The hay costs less than a vet visit for an unhappy or ill pig.
And have a look locally for a good guinea-pig vet. If you can go on their websites and look at each vets speciality. Alot of vets will treat cats and dogs but might not be so experienced with small furries.
Good Luck. You'll love them
Even though my GP2 cuddled me last night and tucked his head under my chin......aaahhh.........then peed.Extensively.Little git. 