I am not in the USA. So we don't get the fantastic deals as much and even if we do you don't earn air mileage.

What I do is just keep an eye out for them daily. This maybe a few of the larger airlines or the no frills airline. IMO, no frills airlines will have more freq sales and if you don't have all the services. That is if you are wanting the lowest fare as utmost.

Thai Airways (Star Alliance) might now and then give $800NZ (New Zealand Dollars) return NZ - Bangkok. AirNZ may give the same or $900NZ NZ - HKG return but AirNZ tend to just have daily specials. So maybe a lot harder to get and hope the dates fall in place with your own dates.

No frills / budget airlines may be $500NZ return all up. Not incl food, tv, luggage etc to say SE Asia but if you want more you need another flight booked to connect. But many times they might only be $1200 all up return. So compared to big airlines they are not that much cheaper. Maybe this can be compared to the big airline's of $1400-1600 fares. So I guess you get away if you don't get food, tv, luggage etc.

I think airlines are pretty smart. They target their competitors prices at a given time.

One time I did get a $200NZ return all up without food etc. Haha. But that was their debut special here.

Got to be careful though as some budget airlines might be more than others after their customers booked all the cheap allocated seats esp around peak season. The fares do fluctuate more than the big airlines. The same week, a diff day could be a diff of 100% in price. Some budget airlines will not include airport fees or tax which can amount to a sig sum so make sure you see the cost breakdown. Also note that the food, tv, luggage cost a fair bit and if you add them all they can amount to the same or more than a big airline. Ie., sale fare budget $500 vs say $800 for big airlines. Likewise $1200 budget not so sale specials can amount to $1500-1600 of big airlines. Also note the luggage excess you will be hammered at $20NZ per kg, if you are travelling more legs like NZ - London maybe $40NZ/kg. Maybe cheapest to add luggage at fare booking, if later you relogin and add it , may cost more and if you leave it to checking in, may cost even more.

So basically for me, I sign up to the few larger airlines and budget airlines on Facebook and emails on their webpages and keep a constant look out. Esp individual airline promotion webpages. The Firefox browser at least lets you bookmark all the webpages in tab. So when you open up in one click all the tabs open up ... that's what I do in many mornings. But I think before all that you need a clear idea of when you sort of can go. You don't want to be caught out, specials out .... ahhhhhhh I am not sure when I can go.

There may be auction pages which the airline participates in too. I don't really use travel agents unless I am travelling in peak seasons.