Well, your target price should be $169.99, as that's been the lowest it's ever been with a coupon. It looks like the most recent coupon expired at the end of June, so there may be one popping up in the next month or so, but that's not guaranteed. The good news is that the current no-coupon price ($199.99) is substantially lower than the introductory no-coupon price ($249.99)
There are three good ways to keep appraised of the prices of HF products. First, hfqpdb.com has a number of digital coupons you can search through by item number, including expired coupons. Second, is the Harbor Freight Coupons extension for Chrome. It's the one Red uses in his videos where you see the coupon price in green when he's on the Harbor Freight website. Third, there are at least a few Harbor Freight coupon apps for you phone or tablet. Mine alerts me when new coupons are uploaded.