I not sure if they're aisle seats. I sit much higher up so my aisle end at 13. I would just do a rough seat count from a picture of the stadium, though I'm sure someone here is in or near that section. I found this pic on flickr
regarding cheaper tickets, the Steelers have a ticket exchange on their site where season ticket holders sell their seats. It's usually up buy now but I just checked and it still isn't. I'm not sure why.
As per your price, I'm not sure what face value is down there but for point of reference, I'm in 517 in the upper level and my seats are $70 each.