Ah, last time I saw it in the store I just saw a package of patties for ~$5.50. I had assumed it was about the same quantity of food as the packages it was next to, but I guess they come in 2-packs compared to the other patties next to them being 4-packs. I've mostly had it prepared in restaurants, with its price comparable to getting the steak option.
I would certainly not call that cheap or even affordable.