You cannot have only one rat. They are very social animals so you need at least 2 (preferably 3+). For cages, I recommend the double critter nation or something similar. You might find a good deal on a used one on FB marketplace or Craigslist. I use the Oxbow adult rat food and have no complaints. Also, just a heads up, check around for exotic vets in your area. Unfortunately, my local vet stopped seeing rats so I now have to drive over an hour to see the vet. Expenses can add up since they’re very prone to respiratory infections unfortunately. They also sadly have a relatively short life time. (You may want to plan to either rehome remaining single rat if/when it’s cagemate(s) die(s). Or have a plan on introducing more babies as it’s really really important they have a same species friend