Not sure what prices are where you are, but $270 for a 1/2oz is way too much where I am(San Francisco) and weed is generally considered pretty expensive out here. The last time I got Silver Haze I paid $180 for a 1/2oz. The most I've ever paid for anything was $210 a 1/2oz for a strain called Purple Erkal that I picked up last week. This was the most potent weed I've ever smoked, however, far more potent than Silver Haze, Sour Diesel, etc.

Think of it this way. If your normally paying $150 you'd be paying 80% more for the Silver Haze. Unless you think it will be 80% better than what your getting now its not worth it.