Um, yeah that is a VERY small cage.
You CAN make a c&c cage for under 20 dollars, it is possible. Look around for sign shops and call EACH AND EVERY ONE. Ask for a 4x8 sheets, and don't buy any of them for more than 10 dollars. I get mine for 8 bucks, so I bet you can find one near you. Then wait for Target to have a sale- they ALWAYS have a 6grid set for 10 bucks. This has 24 grids and 24 connectors. You will probably spend about 20-25 bucks, but then again you can make a cage all the way up to a 2x6. Please look around for this, so your piggy can live in a bigger cage. Also, add more hidey houses. I know you can do this!
Sorry if I came off a bit rude! Welcome to the forums, as I see its only your 3rd post. Your piggy is adorable!! Do you give him a LOT of floortime and cuddles, ect?
You might want to consider adding a second cavy. Two cavies is a must in most cases. I am just about to pm you, so check your inbox soon.