A 3 lb bag of Oxbow will cost around $16 at PetSmart. Their online price is $11 and if you ask them, they will sell it to you for the [cheaper price
] at the store. For a pair of rats, it will last about a month and a half. The kibble in your picture is most likely Oxbow but it could also be [Science Selective
If you need to wait a couple weeks before buying food for them specifically, they should be okay with any leftover hamster/gerbil mix if you have that laying around. I'd avoid guinea pig/rabbit pellets as they're predominantly made from grasses. If you feed your rabbit a mix, that would be okay. If it contains alfalfa pellets, your rats will probably ignore them. If they do nibble on them, it's fine. Even grain-based, low protein dog kibble is okay in a pinch.
Two weeks is a fairly long time but you might be able to feed them human food until you can get them a rat-specific diet. They can eat things like healthy breakfast cereals (Total, Shredded Wheat, etc.), cooked or dry rice/oats/pasta, vegetables, egg, anything "healthy," really. Go heavier on the grains/carbs with smaller amounts of protein and vegetables. Avoid things like uncooked potatoes, uncooked beans, and raw onions. If they're boys, keep citrus to the bare minimum. Spinach is healthy but can cause kidney issues so it's a good "sometimes" treat.
Cheap Cage Accessories:
Rats like to dig, forage, climb, cuddle, and destroy stuff. An ideal cage allows them to do all of these things. Because their temporary cage is a bit small in scale, you could possibly remove the platforms and ramps and fill it with branches, ropes, and hammocks, instead. If they're only going to be in this cage for 2 weeks, you don't need to go crazy, though.
You can easily make hammocks out of any scrap of fabric. Old clothes and hand towels are just fine. You can hang them with safety pins, paper clips, curtain clips, or whatever. Cloth items can get stinky quickly so make sure that whatever you use to hang them can be undone easily because they may need to be washed every few days.
Foraging toys that involve tearing things up to get to food are a great way to provide enrichment. Little bits of food in crumpled up little pieces of paper hidden inside toilet paper rolls or paper egg cartons are fantastic.
When you get a good permanent cage, you really don't need to spend a lot of money outfitting it. Stuff from the recycle bin, backyard, dollar store, and thrift shop can all be used to set up a great cage. A few fantastic store-bought accessories include a [Large Space Pod
] or two, lava ledges, and bendy rope perches.
The [single unit Critter Nation
] would be fantastic for a pair of rats. I quite like [Martin's Cages
]. They're lighter weight and can sit on a table or dresser so they don't necessarily take up any floor space. Either the [Lodge R-680
] or the [Skyscraper R-695
] would be great options. Martin's cages should always be purchased with the powder coating to prevent the metal from absorbing odors.
A decent budget cage for a pair of rats is the [Large MCage
] ($60). It has the same dimensions as the Martin's Lodge (18x30x24). It's not the same quality as a Martin's or Critter Nation cage but with some modification, can work well.
Be careful if you choose to go the DIY cage route. Rats pee a lot more than other small pets and some materials (wood) may not be the best choice for construction. If you must use wood, I'd suggest making sure you do so in a way that prevents it from getting peed or chewed on. You can potentially build a DIY cage for less than the cost of a quality manufactured cage but if it smells terrible or if your rats chew through it after a year or so, you might not actually be saving any money.