I know many of my fellow c-bidders will disagree, but I'm pretty certain that they are two different cigars. I can't PROOVE any of the following categorically, but it's what I think is happening. And FWIW, I'm not a "Gurkha hater," I think people should smoke whatever they like, and there are a few Gurkhas that I will smoke on occasion myself.
The cheap one is rushed, bundled, and possibly even made using other ingredients, and they get away with this by having it be a special "exclusive" size. Although the blend may be similar, it's not really he same cigar in a different vitola.
Also, Gurkha does not OWN any cigar manufacturers, factories, fields, or anything else really. They just buy specific crops of tobacco, and pay a factory to roll the sticks. Therefore, by the very nature of their business model, consistency over several years is very, and I mean VERY, hard to come by.
The typical scenario goes like this: Gurkha buys some top-notch tobacco, rolls some very good or even down right great cigars (the original Legend, Centurian, Signature Maduro, Beast, Titan, Beauty, Genghis Khan ... all excellent). They are well-praised, sell well, etc. But when the initial tobacco runs out, the don't cancel the cigar ... they keep making it using "similar" tobacco. But the vast majority of the time, the subsequent cigars just aren't the same.
I think there are plenty of Gurkhas worth $2-$4, and a couple worth $5. But I'd not pay more than that for any, of course that's just my palate talking. Smoke what you like!
Aside: This example is why I'm a very big supporter of Nick Perdomo. When he runs out of the right tobacco for a cigar (or cannot source it anymore to meet the proper quality), he just cancels the line. He has cancelled some of his best-selling cigars for this reason. Now, he typically comes out with something similar shortly thereafter, but he does NOT put out something similar and pretend it's still the same cigar. That kind of leadership earns my respect.