My friend is an idiot that owned the car before me and switched a brand new tire in one spot on the front right of the Disco. The rest are bald, I haven't had the money to get the other 3 and I don't know when the car was aligned last. The car vibrates at 70mphs and since my friend owned it, I know it used to drive very smooth at 80mph. Basically just hoping I need an alignment and some new tires, is that what it sounds like to you guys? Also if you just barely steer to the right or left it stops briefly another hint to me that I just need to get it aligned.

 

Sounds like a tire out of balance. Until you can afford 4 new tires put the spare tire on the same axle as the other new tire so that they are the same size tire on that axle. A worn tire is smaller than a new tire. Then put that bald tirein the place of the spare.
Stay under the speed at which it starts to vibrate.
Do you feel it in your seat or the steering wheel? In your seat means back tire, steering wheel front tire.