Other than buying them, no.
There are wings on costumes but there are no wings just by themselves!
There is no way to have a bat follow you on any island. This may be an idea for the costumes at the Store.
There is some on Super Power
Poptropica's paid monthly members can use (but not keep) any of the costumes or effects (gold cards) in the Store, including the Multiverse rooms, and have Early Access to all new islands when they are released. The membership is a monthly fee paid by credit card or Poptropica Gift cards.
yes the hypnotic
No. You do not get any actual Credits, which must be earned or purchased.Paid monthly membership lets you "use" any costumes or effects in the Store, and gives you Early Access to all new islands (about a month before non-members). But if your membership stops, you do not retain the costumes, effects, or Early Access privileges.
Yes, many of Tinkerbells friends have costumes. These can be found any place selling costumes around Halloween and at the Disney store.
The costume, like others at the Poptropica Store, has an effect built in, but will not change the play of any Poptropica island or game.
There is a dog suit in the Poptropica store. It does not affect the play of the islands in any way.
You get an Island Medallion for completing the quest on any island, but only once. You also get 100 credits toward costumes and effects at the Poptropica Store. Once you have completed all 9 islands, you can only play the Main Street games and any advertising mini-games that are posted. The only way to play an island again is with a new avatar (you cannot combine credits among players).
One of the best places to get any type of costume is Party City. They have a huge selection of costumes in store and if you do not see it in store, it will definitely be available online.
You can buy Nun costumes any time of the year online at Party City, Amazon and Spirit Halloween. If you are looking to buy these costumes during Halloween time then you can purchase them at any store that sells Halloween costumes.