It depends on which tree you want to train on.
It takes a week and a day (source) 99 Woodcutting :D
you should stop woodcutting
You keep training your woodcutting or ask a friend to do it for you.
10,613,344xp
1,228,825xp
It won't work. You will be caught, and your account will be banned.
$100 for sure
This entirely depends on what level you are starting at and what you are using to train the skill.
513 Hours Mostly like 2-3weeks
I bet a few hundred people are pondering over how long it will take. From 78 Woodcutting to 99 Woodcutting can take from months to weeks, depending on what you want. You either can go for Money or Experience; Ovbiously everyone would want Money, However! The money way will take any where from 3months to a year. The easier route (That would make more money in the long run) is Ivy the 2009 Update, currently the fastest way to 99 Woodcutting. Requiring 68 Woodcutting, it is VERY popular. This is the best route.
level 99 woodcutting.
like a week if u play for 2-3 hours a day