You answered your own question. All the Subaru GTs are turbos now. The turbos are hard on gas, high maintenance and expensive to maintain. The base 2-3 models are normally aspirated and less expensive to run. Other than that they are great cars.
My recommendation would be the 2.5i Special Edition car. That today represents one of the best values available in the entire automobile market. The Limited adds a few nice amenities such as leather and dual climate control, etc. Mechanically they are identical. A very difficult car to find on the pre-owned market. Look at the incentive programs on the new ones. Might be within your range.
get the GT you will regret getting the non turbo legacy because its so slow.the premium gas will cost you something like $400 more per year. don't let that stand in the way of getting the car you really want
Now for the downside.... I owned a 93 Legacy & found... Very expensive for service & parts. High insurance costs. Hard to find a mechanic who knows them well. Thirsty boxer motor & not very powerful. Tyre wear problems. Interior trimming fittings cheap. Not the best paint finish in the world. But otherwise not a good car for impoverished student. Get a Toyota Corolla