the same amount
you get a lot of credits by completing lots of islands...
by completing the game if there is an ending
No, you do NOT earn credits for restarting and completing an island in poptropica.
Credits can only be earned by completing islands or by purchasing them. There is no other way, legal or illegal, to get credits.
Impossible
Currently they can only be obtained by completing islands or by purchasing them at the Store.
There are no cheats to get credits. You can only get credits by completing islands or the little place like don't be an energy hog.
There are two ways to get free credits on Poptropica: 1. completing islands give you 100 additional credits. 2. Buying new credits online using a credit card.
A course is usually completed after you have taken the final exam. If you mean, "when have you completed ALL of your college coursework", this would entail completing your major (usually 30 credits or more), completing all distribution requirements (somewhere between 20 and 45 credits, usually, depending on the college), and completing enough elective coursework to finish with the 120 - 124 credits needed for a bachelor's degree.
You can get free credits on Habbo by completing survey's or other means. To find the full list, go to: habbo.com/credits
You can earn Habbo Credits by completing the free offers for credits located at the link below. Be careful - some offers requirement payment and you to enter in your personal details.
There are no "secret credits" on Poptropica. You earn credits by completing islands, or by an adult purchase in the Store. You get 100 credits for completing any island, and 50 points for the Haunted House, Earth Day game, and Dr. Hare's Secret lab (Earth Day available free through the Poptropica Store). Each username can only get credits from each island once, and points cannot be transferred between usernames.