Use ITA. It will show the current available fares, regardless of whether the airline is marketing them as "promotional" or "sale" or not. Find your ideal flight there, and go directly to the airline site to buy it.

(Talking published commercial flights only, of course.)

Flight + hotel combos are almost never a good deal, IME. Either (a) I can simply get the same or better deal by booking both directly, (b) I don't get my hotel elite benefits when I book the combo, or (c) the combo ends up booking through a third party agent for *both* the airline and the hotel, thus exposing me to greater risk during IROPS, greater hassle if I ever need to change or cancel a trip, and often less functionality (check-in, seats, etc.) on the airline and/or hotel websites.

If somebody has a travel agent or website that actually has screaming-good package deals, I'd be interested to hear it. At the end of the day, it would have to be a TA with access to amazingly cheap (as in...damn near free) hotel inventory that somehow nobody else has. The other way...a TA with amazingly cheap (yet still mileage, status, and upgrade eligible) airfares that they use as a hook to get you to the hotel seems like an extinct species unless you're in a targeted high-value group for a particular casino hotel.