Well, buy them.
That's the only way, other than making a new account but I don't know if they still give out free ones to new users.
No, you do NOT earn credits for restarting and completing an island in poptropica.
100 like every island
buy them
You go into the future and talk the the future you, and she/he will give you the medal.
no
Your credits are added to your account when you receive the Island Medallion. If you are in doubt about whether you have won, check the Star Menu (upper right) for your status, and it will show the last four or five things that have been added.
There is no way besides winning them or buying them. Unless you can get someone else to play it for you. You can also earn credits for beating Earth Day or the Haunted House, which are mini-quests available in the Poptropica store.
early poptropica
Every time you finish an island you get 100 credits.
save your credits ever time you finish a island
you go to the poptropica store and look for it in the costumes. P.S.- you cant get it with out credits from beating islands or buying them
That's the only two ways.