Questions for getting guinea pigs...

Hi! I'm currently considering getting guinea pigs. I have owned them before when I was younger, and they've been one of my top favorite animals ever since. I've done lots of research over the years. I would really love to adopt some.

I'm 15 (I know it's controversial for minors to own a pet; I have all costs/vet/etc figured out, my parents are cooperative and willing to take over their care if needed). My parents make me save up the startup costs of any animal I get (they pay for maintenance and extra stuff after that). I will be the primary caretaker with my parents checking in once in a while, it has been like that in the past when I was the main owner (betta fish in the past and currently a senior mouse) and it has worked well, so I am confident that I am able to provide proper care for them.

Anyway, with that said I have a couple questions:

I currently have $385, and I was wondering if it was enough to get started? Not including an adoption fee.

Ideally, I want to get an already bonded female trio, although I'm open to less pigs or male pigs. But I probably will need a 2x5. How much did making a cnc cage cost for you (if you've ever gotten one) and how big was/is it?

Where can I get a good fleece liner? I'm considering guineadad but would like other options. Back when I had guinea pigs, I used bedding.

Lastly, we have a family dog (mini bull terrier) so I need to keep the cage up high, like 3 feet maybe? He's about 14 inches talk at the withers. He's friendly and has basically no prey drive, he just occasionally looks at them out of curiosity if he sees a small pet. So he won't try any shenanigans, but obviously they still need to be out of his reach.

Anyway, I was wondering if there are any methods for this, or maybe some sort of table I could buy if it fits the budget. I was thinking I could prop it up with cnc grids but I'm worried about how strong they are? My past guinea pigs were in store bought cages (it was before I was educated; later on I provided them with more space but I used parts of cages that I already had, not cnc) so I'm not sure how much to trust the strength.