No.
Unless you loaned the DSi, there is no monthly charge after you bought the DSi.
no
You do not have to pay any money, above and beyond whatever you pay for your wireless internet connection, or any DSi points for use in the DSi store.
No.
if it is dsi ware yes
Monthly Income!
Yes it is a Monthly pay $14.99 a month or you can pay $119.99 for 1 year.
Monthly Income!
T-Mobile offers pay as you go plans. They offer pay monthly plans, pay monthly phones, SIM-only monthly plans, and pay monthly deals. They offer 18 or 24 month pay monthly plans with the latest phones.
You need to connect to the DSi store, and pay for them there. You can then download them to your DSi.
If you want service you will pay a monthly bill.
no