Lol, that new boy has a nice bubble-blowing talent their :) Chinchillas sound cute, like a pet you could cuddle with. What do you think a min. Cage/tank size for one is? Or are they like rats, where they need pairs?
No, they absolutely do not need pairs. They do fine alone.
I'd say one that is absolutely at least 2 feet tall with at least 3 levels. Including a wheel, enough room for chew toys, a chin-chiller, a wood block, and enough room to jump and run around. It should be at least 4 times the chin's body length from tip to tail.
Well, these things can cost 175-1000$ themselves depending on color, breed, health, where you get it from, and gender. You can get a cage like mine for 500-1000$ new, Then you need food, about 10-15$ monthly, then chew toys, 20+ those can last a few months, other toys can range, water bottles are about 5$ each, food dishes for all the food can be about 15$ for 3 bowls, chinchillers are like 10$, Wood perches are like 4$ each, then all the levels and building and stuff can be about 40$