Nothing, or at least nothing more than a few bucks.
I can only enjoy a purchase of any significance if I feel like I've gotten a good deal on it. Part of it is a residual appendage of the days of being very poor, in which finding a truly remarkable deal for something was a necessary baseline to even consider it. I have a very, very hard time enjoying a purchase if I didn't get a tremendous value on it, even though it's no longer necessary.
And part of it is just that I get enjoyment out of it. I enjoy the entire process and delayed gratification of shopping, researching, shopping, scanning deal sites, jumping on a clearance item or a temporary sale, etc. I just enjoy that process and it adds great satisfaction to me. There's no other good explanation why I'll dick around for three weeks until I can get a $70 item for $50.
I'm in the same boat as you as far as my wife. My wife will walk in and buy that $70 item for $80 if she can go into the closest store and walk out with it. And I can't rationally explain to her why she should give a crap about the $20-30 extra, because she shouldn't. And yet it will nag the back of my mind if she does and keep me from enjoying it.
At least I've gotten away from it on restaurants, which for years we wouldn't go unless we had a coupon or they had a big special. My kids still joke about every dinner out revolving around where we could find a coupon. While I'll still jump on a coupon where I can, we've freed ourselves from that. And on purchases, it doesn't take me nearly as good a "deal" to pull the trigger as I used to.