gistfile1.py

class Product(ShopifyResource, mixins.Metafields, mixins.Events):

    def price_range(self):
        #prices is a list of unicode strings not floats       
        prices = [variant.price for variant in self.variants]
        f = "%0.2f"
        min_price = min(prices)
        max_price = max(prices)
        if min_price != max_price:
            return "%s - %s" % (f % min_price, f % max_price)
        else:
            return f % min_price