But before you condemn my point entirely, consider this:
If you're buying in software, consultancy, per-project services etc, then the primary levers you can adjust are commercial terms. You might feel exceptionally good about reducing the cost of a project by £5K or shaving a couple of points off margin, but do you really think those suppliers are going to produce exactly the same output for you and just make £5K less on the deal? Good luck with that.
If you're building your own products, and assuming you've got a fixed size team, then the primary levers you can adjust are tradeoffs and shortcuts - i.e. where you spend your time. How you pay for quality is then divided up between how much you're prepared to pay for now up front, and how much you're going to pay later - typically through higher operational or technical support effort (less automation), increased cost of the next features (technical debt), and opportunity cost (revenue lost to product unavailability).
So I'd suggest that you always pay for quality, whether you intend to or not, and I'd add that it's usually less painful to pay for it overtly through a proper project plan, than inadvertently through reactive support, interest payments from future projects, and your customers patience.
I'm not saying that you should never try to sharpen a deal to save some budget or take a shortcut to get a product out quicker, simply that you should keep in mind the longer term costs as you congratulate yourself on the shorter term gains.