It depends on what kind of tournament you want to enter. Most local tournaments don't cost anything, but some higher ranked tournaments cost around $5-$20.
a starter deck is fifteen dollars but if you want a kick butt deck, you are going to tune it out with booster packs
It depends on the type of tournament. Local tournaments are usually free, but other bigger tournaments could range from 5$ to even 30$
Anywhere from 10 to 20 dollars.
around $60
It costs $12.65 on amazon.com