Plus if I reflect and later decide I do want what you're offering, then I know your "full" price is bullshit and your "special" rate probably is too, so I'll come in negotiating hard, both because I've learned something about your prices and because now I kinda don't like you.
Salespeople pull this crap with all kinds of things that don't really have any actual time-pressure on them, though. Home remodeling, various services, unremarkable (that is: not unique or highly in-demand) cars. In fact, "we're running a special that'll get you 10% off if you sign today" is usually a strong indicator that I can ask for 15-20% off tomorrow and get it. If that kind of salesperson offers you a "deal" unprompted, then that "deal" is actually their price for suckers. I hate that kind of thing, don't like being manipulated, and don't like it when scummy salespeople win. So I'll either look somewhere else or take that newfound knowledge and ask for something better than the "special", on my own timeline, not the salesperson's.
We eventually settled on a IKEA kitchen, just because they are fully transparent and offered what we needed, with no pressure or tricks. And I got the chance to build my own kitchen, which was a nice experience. If it was not for their limited choice of options they would be the only contender for our next kitchen.
I think that's good. They can't promise you any upcoming sale as they don't get to decide on that, but they know the sales generally come up on X day of the month/week.
It's like when you interview for a new job and ask you if you are interviewing with anyone else, why would you ever say no?
But yeah like moshmosh said, real estate is different. Anything where you are vying for exactly one of a thing is a different beast than whatever crap you SAAS vendor is trying to tell you.
Also, real estate is an exception because:
1 - there is actually scarcity. A building with 200 apartments only has 200 apartments.
2 - Some buildings are already (almost) full, so you can only get in when someone gets out.
But what I see here where I live are offers that are valid for a whole month or two. Of course, if all units are taken, then you can't get it, but if they have an unit available, the offer is good
This works particularly well for large one-time sales where pricing information is scarce and the relationship is less important. Example: sales for replacement windows, doors, roofs, etc.
I've also adopted the principle that if someone comes to me with an offer, it must be beneficial for them. This is especially true for door-to-door salesmen and utility contracts. Like they give you a big (like 50%) discount on electricity, but the gas price is where they get you.
That's legitimately horrifying. I've never had the misfortune of experiencing it, but now I know - if a salesman ever tries to pull that tactic on me, then instant threat to call the police.
I was at a Honda dealer once, having owned Honda and Acura cars in the past, and thinking about a hybrid. I said something to the salesman about Honda hybrid drivetrains being second rate, engineering wise, compared to Toyota, even though I generally liked Honda vehicles in other respects.
I was startled when he seemed to take it really personally. It didn't seem like he was just acting angry - I can't see what the use of that would be.
WTF? I would never buy anything from someone who's getting angry at me. If the sales experience is that bad, what can I expect from customer support later? Threaten me not to open any support ticket?
Conversely, I've had a good experience with this. I was buying suits for the groomsmen in my wedding, and the salesman offered to hold everything until the following Thursday because there was a 15% off everything sale that day. He put them in a closet and I came in on that day so he could ring the sale and I'd get the discount.
Now I permanently associate exploding offers with long-term dissatisfaction of the product.
Use this as an opportunity to inform people about the dangers of proprietary software.