Absolutely!
You will just activate a new number with us (with the phone of your choice). Once you are satisfied you can port over your number you can keep the trial number or abandon it.
Also, you can use the same phone for the trial and then put it on the ported number later. Just tell us what you want.
Now, keep in mind that you should activate only a $10.00 pin. When you port in the number from your old carrier and abandon the trial number you will lose any remaining monthly plan on the trial number. A monthly plan cannot be transferred over. However, any cash balance on the trial number can be transferred to the newly ported number if you wish. Of course you can keep the trial number should you wish by just putting a new phone on it and you can retain everything on that line as you normally would.