I think for standard It's 30 for the first pair, then 10 gallons per additional pair
Dwarves are a lot more complicated. I remember reading that they have to be kept in groups of 5 or more and in no larger than 10 gallons...
I picked up the Cannon T7 from Costco, it cost about 500 and it came with a macro lens. I can upload some pics I took in a bit (my build thread is severely behind)
I'm planning on getting a 100mm macro lens down the road too, but it'll cost as much as the camera.