Okay, okay, okay. I'm interested.
Here's the problem I have with a "constant sale" model:
Product is purchased from distributor/manufacturer at a price of $xxx.xxx and agreed to be sold for a price greater than or equal to $XXX.XX by the retail channel. The numbers determined by the involved parties (hopefully) are well planned and allow everyone to benefit: manufacturing/distribution, retail channel, customer/end-user.
The retail channel begins to discount product to compensate for unsatisfactory sales figures (for whatever reason) and increase sales volume. Simple strategy, right?
The customer/end-user appreciates the reduction in cost from the retailer and enjoys the same great product normally priced at $XXX.XX for $XXX.XX * (0.85), or some number less than one, thus saving $XXX.XX * 0.15, or some number less than one. Everybody is happy. Manufacturing/distribution is getting their product bought and sold, retail channel is pushing weight, customer enjoys spending less money on product and more on beer.

Concerns arise when observing where the function converges, or the end-behavior of the function.
Lets talk about something many of us can relate to: dope.
I'm going by the prices in the bay area around 1995 - 2000, so if shit seems strange by today's standards, or even your own in that time/place, just substitute your own prices and linearly scale the prices.
An 1/8th (3.5g) typically costs $50.
A dime (0.5g) is $10, and a dub (1g) is $20.
If you knew people, maybe you were paying $45, or even $40, but at $40, it was rare that it was sticky-icky-super-chronic.
Either way, a new dealer decides he wants to get in the game. So he buys a zip. He got player pricing and paid $275. Not bad for the new kid. Sold in 1/8ths, he stands to make $125 ($50 * 8 = $400; $400 - $275 = $125).
However, he realizes that if he's pushing at $50, he's not offering anything anyone else isn't; and everyone has the shit. Or at least acceptable commercial grade shit.
So our hero makes the realization/conclusion that if he cuts a little of his profits, he can earn more customers. So he's pushing at $40 / 1/8th to gain customers. Sure he's only gonna make $45 on the zip rather than $125, but he's gonna flip it in an hour. Totally killer.
Aside from pissing off the other dealers who are losing market-share (customers) our hero is inadvertently fucking himself out of his own money. But you have to look at the end behavior of his actions to see it (assuming he isn't shot for pulling this crap).
Everybody in the bay is used to buying $50 1/8ths. Now they can get em for $40 if they call the new kid. So the new kid gets all kinds of business and before he gets shot, nobody can sell an 1/8th for $50; they gotta sell it at $40. That means EVERYBODY is making $45 / zip unless they're pushing weight or have some better pricing, even under those terms, their still not making the cash they were when 1/8ths were $50. Well, the value of pot drops to $40 / 1/8th and the days of $50 1/8ths are behind us. Pretty tight for the smoker/customer, but fucked up for everyone upstream and here's why:
The new kid gets sick of making $45 / zip, because that's a lot of risk for $45 bucks. So he demands better pricing from his distributor. If he doesn't get his ass kicked, the distributor has to cut his profits to satisfy the new trend appearing in the market: $40 1/8ths. Follow it a little farther and the distributor is bitching at his grower because he's not paying $1600 / lb anymore, he only makes $200 on the deal, and that's a lot of work and risk for $200. Now he wants to pay $900 / lb. Assuming the grower doesn't shoot him, the grower just lost $700 / lb, which would be fine if he didn't care about money, but he's got a kid to feed and bills to pay. Which means he's gotta do something to compensate. Maybe that means shorter cure time, maybe it means less tight a trim, maybe it means more plants in the same amount of light, etc., etc., etc. The bottom line is dope is $40 / 1/8th now and nobody is paying $50.
That's fine, but now the new kid doesn't have any competitive advantage, AND he's still not making money like dudes used to before he pulled this crap, so he cuts his price to $35 / 1/8th. Assuming the tennis shoe ballers on the corner don't shoot him for fucking up their hustle, he's further depressing the value of the product, and while that is tight for the customer, as the trend continues, distro starts pushing blow because the money is better. The growers pack it up and move north because that's just how it goes, and nobody wants to get into the pot game.
Then the customer doesn't have any weed. And that's weak.
Really, this is just basic economics. Its frightening that this kind of shit is tolerated, but hey, you can't really control the behavior of others, without LSD.
Enjoy the sales while they're available, and don't be shocked when that radical discount company mysteriously shuts down.