Yes! While on your free trial, you have full access to all PRO features, including the Goals & Rewards Dashboard. That said, you do need to have a credit card on file in order to turn on all the rewards options, i.e. Count.It won't pay for your gift cards!
So, while on a free trial, if you want to turn on automated gift card rewards, simply enter your credit card info on the PRO Admin --> Account page. Not to worry, just because we have your credit card, we won't start billing you for the PRO subscription. Just the gift cards. Or, if you simply intend to have non-cash rewards, you can set your goal, and then just choose the "OTHER" rewards type, which allows you to describe your reward.