you can not.
you can't design a costume,but you can get a lot of different kinds
Apparently not. But there is a costume store.
On Main Street of Super Power Island, go to the Masks and Capes costume store. You do not have to wear a costume, but you do need a Super Hero ID card.
Well, you could try the Internet to buy a Power Rangers outfit. Or, are you talking about a Halloween Costume? If so any Halloween Costume store would probably sell it.
Go to the Masks and Capes costume shop and get an official Superhero ID from the owner. You do not have to wear a costume.
You get one from the Costume Shop. You do not need to get a costume, but you need the ID to go to the County Prison, and to record your arrests.
The masks and capes are permanent costume items until you remove or change them. Unless you purchase a costume, it is not selectively put on or taken off. You automatically lose your flying power when you leave the island, as it only works there.
At the Masks and Capes costume shop. (Costumes are not required, but free.)
When you arrive on Super Power Island, the County Prison is across the water to the left of Main Street. Once you have a Superhero ID from the costume store, you can go there for information.
To get the superhero costume, you go to the capes and masks shop on main street on Super Power island. just click on one of the costumes to the right of the entrance :D
It is not a costume. You earn the power to fly by defeating 5 of the 6 super villains using your wits alone. Then you will receive the flying power to catch the 6th one (Betty Jetty). (see the related question)
After you defeat five of the villains, you can fly. That's the only power you get. (But there are some pretty cool super suits at the Masks and Capes costume shop.)