Is $165 + tax for a MAC a good deal? or do MAC ALWAYS go on sale for that price?

That seems to be the standard price for MACs on sale websites like Gilt and such.

I personally think its a good price since there are people selling MACs on Bonanzle, and eBay for more than that. It also depends on the color you are looking for.
 
The MACs on Gilt and the RM OSS are often specially made for that sale, but there are also mainline bags in the mix. So if you get a mainline MAC for $165, then yes it's a great deal. For those resold on ebay/bonz, the price is usually going to depend on how rare the bag is,the color, and condition.