I too found a lot of deals on Amazon, especially for cases. Plus if you are a prime member, 2 days free shipping too, which adds up to be a lot of savings.
For (aquarian) heads, though, I have found the same heads at the local shop that I buy from to be just about the same cost.
When I shop anymore for new (and used), I look at Amazon first an then reverb.com. I have also found that if you call the stores (like chicago music exchange, dales, drum center, sam ash, etc) for new items (not avail with Amazon Prime) they tend to give lower costs than the internet prices. The exception to the rule is GC, though every so often they will do the same. The really hard part to beat with Amazon, though, is the 2 day free ship for prime.
For the most part, if the local store (including GC) has an item in stock I will try to buy locally unless the price is way out of line (which is rare - most match internet prices these days if they can). If they do not have it in stock, though, it is usually quicker to get it from Amazon.