Hey Mark,
First of all, let’s clarify what you mean by “…just have to pass my tests…”. If that means that you just need to take the checkride, then make sure you do that as soon as you can, you don’t want all the hard work you put into flying to slowly get away from you before you take the checkride. Now if you are talking about the written exam, then I’d recommend waiting on it until you actually start training again. The score report is only valid for 2 years and since you are a freshman right now, it wont count when you will need it in 3-4 years.
Now with regards to flight training costs, ATP specializes in a fixed cost program. You can see the different programs here (scroll about half-way down the page and you will see a comparison table). The details of each program have been dissected in a few posts (post #1, post #2) so you can read through and get an idea of what to expect from each.
Extra costs on top of these prices are going to be:
Flight gear - ranges from $200-$2000 depending on the equipment you decide to to get.
Checkride fees - about $800 per checkride (8 in total including private)
Housing fees - ~$5200 for ATP student housing option
iPad apps - $100-$150 (you can get Foreflight for free. Check this out for details
Let us know if you have any other questions.
Yarden