Forget the power. By your own statement, you can’t afford it …the most reliable and inexpensive awd car with the best mileage will be a used Toyota Matrix and it’s clone from Pontiac, the Vibe. A used WRX is is a potential high maintenance item that could easily have been abused more than the average Subaru Impreza, which would be my second choice with the standard motor. In that form it has good power and is quite reliable.
Otherwise, get a Corolla/Civic/Focus with good tires, it’s a lot cheaper.