As a woman who has been bargain shopping for 30 years, I can tell you that price matching is not considered another offer. This only refers using two coupons or some other kind of special that the store is offering.
I have used coupons on top of price matching many, many times and it is a perfectly acceptable and legit consumer behavior.
I also question that you could not get a price match on your first choice of items. Regardless of selling under cost, stores that offer price matching should do so on any item. I'm not familiar with Sony Style's policy so if they don't usually offer price matching then it's acceptable.
By all means - use the coupon!