Doing braces is not a pain at all, at least for me. you'lll get used to it. for me, the only time when it feel pain when i just tighted the braces, the ,morning after i wake up. but my problem is i can't avoid eating hard food(fried chicken, snakcs etc) that affects the braces. i wore braces for 4years + now, and only seen abit difference.

pain is not the thing u need to worry. if u really want to do braces, this is some thing that u need to sacrifice :

1. money
2. time(for treatment)
3. food(but i eat all thing  )
4. losing some strong teeth to make space.(my case, i lose 4 teeth)

to enjoy
1. choosing colour of braces every month.
2. attention from people.

pain only during activation period. you may try eating painkillers after activation for 1 day.
RM4000 onwards, depending on area and 'difficulty'. instalments in cash interest free. if credit card, there may be some interest.
no age limitation. but they might want to asses your gum health prior to treatment.

let's not think of 'fastest' treatments. those who keep pushing to rush, may not get the results they're expecting.