If you've downloaded the game and installed it, you should be able to fire it up and fly around offline to get the feel for the flight model and controls. Once you decide to go online, it should walk you through setting up an account but should not prompt you for any bank info. You should then be able to do anything in the game for the two-week trial.
The only hiccup would be if you've already created an account and had your two-week trial period sometime in the past. If you're sure you've never used the trial period, you should contact HTC and get it sorted out. They're a great group of people and very responsive.
Tech support can be reached at support@hitechcreations.com. Account and billing support can be reached at billing@hitechcreations.com. They usually respond within one business day, so you'll have to wait until after the weekend for a reply.
