Normally $USD49/year, TripIt Pro will be free for 6 months according to their website.
"If you’re new to TripIt, sign up between March 13 and March 31, and we’ll automatically give you access to TripIt Pro for six months.
If you’re using our free TripIt service, update your account by March 31. For existing TripIt Pro users, we’ll be extending the same value to you."
really like the free version so will sign up for the upgrade