Not to be mean, but you do realize how much work/time/money guinea pigs are? I can't drive either and with school and all, its hard. Guinea pigs do best in pairs or herds. So if you are getting one, you should get another one or none at all. They need unlimited hay and pellets. They also need at least a cup of varried veggies a day. SO with two guinea pigs, its already 2 cups of veggies a day. Also, the minimum cage size for two sows is a 2x3, for 2 boars, 2x4. Its alot of space.
Also, you will need bedding which has to be cleaned at least one a week. Fleece is what I recomend. That requires shaking it out and laundry. If you don't use fleece, carefreesh or yesterdays news gets pricey.
Guinea pigs require out of cage free rome every day. I admit, considering I am a minor, guinea pigs are really hard to care for, harder than you would think. I save all of my birthday money and holiday money to provide for my guinea pigs. I also babysit and its pretty tight. I pay for everything, and its hundreds a year.
I ride my bike to the food store to get veggies. If you can't drive, like me, your parents will have to commit to driving you to vet visits, another expense. An average yearly exam is about $30 per pig. Sicknesses can get very pricey.
Guinea pigs are great pets, but are not for everyone. You need to commit and they can live to 8. So do your homework before you get one or hopefully two.