Hobby King batteries are like 1/4 the price of the name brand. If 3/4 batteries you buy from them are bad, you are still 'breaking even'. Millions of people use them, and we all know that 3/4 of the batteries you get will not be bad, so they are worth it.

They post 2 weights - 1 for shipping (heavier) and 1 for pack weight. The common trend is that the batteries actually weigh a few grams less than posted. Maybe not always the case, but most of the time.