I got a flat today... What now?

[Captain Slow]

Hello there.
I seem to have picked up a very large nail in one of the tires on my '06 Outback. It was long enough and hit at the right angle to go through both the tread and the sidewall, so I'm assuming the tire is beyond being able to be repaired safely.
This leaves me in a tight spot, because now I'm looking at spending $500 or more on a new set of tires, because at least as I understand it, Subaru AWD needs four identical tires. Unfortunately, I'm on a college student budget and would like to avoid spending this amount of money.
So my questions are:
1. Is it REALLY true that you can not put on two different tires on a Subaru?
2. Is it a good idea to get a set of used tires? For example, I found a set of 4 Yokohama Geolandars w/ 60-70% tread left for a little over $200 on Craigslist.
3. In the event that I do need to buy new tires, what are the best ones for a low price? I do enough driving on dirt and rough roads that I want something that will perform well in off-road conditions, but MPG and road noise are a concern. What have you all got on your cars?
My current tire size is 225/55/17 on the stock OB rims.

 

[idw]

It'll be fine just get a new one

 

[Red XS]

Subaru say you can have a diameter difference of up to 8mm. So if you haven't yet used 4mm of tred you're within tolerance and there shouldn't be a problem. Would only be a problem if your current tyres are getting low and then you'd be looking at a new set anyway.

 

[Robbks]

I've seen the results of 2 new tyres and 2 that are "half worn" in 3 separate vehicles I've bought.
two with cooked centre Diff's and one with worn planetary gears in the rear diff

 

[Liberty Valance]

Uni student hey..... buy one new tire and put it on the front. Put the car into front wheel drive by using the FWD fuse.

Drop a bit of oil under the new tire and do a huge one wheel burnout to impress the college girls. Stop when new tire diameter matches the other three!

 

[Kevin]

:lol:

 

[MiddleAgeSubie]

Subaru say you can have a diameter difference of up to 8mm. So if you haven't yet used 4mm of tred you're within tolerance and there shouldn't be a problem. Would only be a problem if your current tyres are getting low and then you'd be looking at a new set anyway.

We wish.

What Subaru says is 1/4" or 8 mm of CIRCUMFERENCE.

Basically, anything more than 1/32nd in treadwear difference requires full set replacement. In the US, Subaru dealers are so strictly instructed about this rule that even mod-friendly ones obey it to the letter.