Jetstar is running a promotion which offers $1 fares to anyone signed up to its mailing list, which sounds like an amazing bargain at first glance. But it doesn't take too much digging to establish that your savings will very probably be slight at best.
Unlike earlier Jetstar discounts which only went to customers of the Jetstar-branded Mastercard, this one is pretty much open to anyone (provided you don't mind being on the mailing list). Nonetheless, the conditions attached are so onerous that it's highly unlikely you'll get a bargain. Here's the deal: You have to book a return flight before December 13, for travel between December 6 and December 22. That means you won't get cheap advance notice fares, you're moving into the busy school holidays period, and you can't use the trips for Christmas catch-ups. In other words, it's unlikely to be unusually cheap.
If you meet these conditions and ensure your flight is booked with your registered email address, you'll be sent an offer featuring "the $1 sale and other amazing sale fares to selected Australian and international destinations" at some point in January. There's no word on when you'll get it, what time periods it will apply to, or which destinations will be included. The only information is that it won't include flights to WA or the Northern Territory.
In other words: you have to spend close to the maximum amount of money on a trip you weren't planning to take in order to possibly get a discounted seat for another trip you weren't planning to take on an unspecified date for an uncertain total cost. Sounds messy to me. It's entirely possible that two return trips booked further into the future would be cheaper than the sum total of two return trips booked this way. That's especially likely to be the case if the $1 fares (like many other airline discounts) turn out to be in one direction only, meaning you pay full price for the return leg.
If you genuinely need to book a flight in that time period, it's an interesting offer, but it's nowhere near as good as the "$1 fares!" subject on the email makes it sound.