Personally, I'd weigh the pros and cons of getting one or the other. Consider prices and how much a new planted tank and betta would cost in comparison to how much the iPad would cost, plus a cover or whatever else you might want for it as far as accessories go. I got a Kindle Fire HD for Christmas, and while I love it, I hardly use it because I have a laptop and a smart phone. I'd consider that too, if you would really use it and if you think you would enjoy having the iPad more than a new tank and betta.
If I were in your shoes, I would go for the tank. If I were in your shoes, I also wouldn't be going to college this fall, so I would be able to. xD (Though I can't say I wouldn't like having the tank, plants, and betta as a gift. Maybe I'll ask some of my friends or family to give me some money to fund my obsession so I can get my babies their tank for college.) I guess it depends on what you already have though, too. Like if you already do have a computer and/or smart phone, and how many fish and tanks you already have. If you think you'd be able to care for the new fish as much as you do the others, it wouldn't be a bad idea. :) If you get stressed easily or don't really have a lot of time, go for the iPad, so you don't have to worry about not being able to clean the extra tank. It's a hard decision and I totally understand how hard it is to choose between technology and fish.