Personally, we'd rather hit up one of Paris' many patisseries than chew on some fluffy sugar, but to each his own. C'est la vie en rose! Also, not surprisingly, cotton candy at the Eiffel Tower is also the name of a nail polish color.
The Eiffel Tower is open every day from 9:30 a.m. to 11 p.m. but will extend its hours for the summer season on June 1st. Tickets start at 14.5 Euros for a ride all the way up to the top. You can also opt to go just to the 2nd floor for 8.5 Euros. Just be sure to book your ticket online so you can skip the terribly long queues when you get there.