The clock and the pocketbook

Back in the day, before the economy started tanking, I never had much doubt about what I would prefer to save when it came to time and money.  But as prices keep rising, I'm rethinking those priorities ... at least when I can figure out how to do that.

After all, it's easier said than done, right?  Today, I went shopping at CVS where I saved big bucks on sales of Aveeno suntan lotion (I'm hooked on the SPF 70 spray) and Listerine (which was great since you can practically go bankrupt in the  pursuit of dental hygiene).  Then I filled up my 2001 Subaru with gas at $4.33 a gallon, which felt like the biggest bargain on the planet, since I haven't seen a price that low for more than a month.  

What a day.  I felt great.  But because I was racing around like a maniac, I took a short cut to get the shopping done, which involved driving over a toll bridge ($2.75).    By the time I got home, I realized that, mathematically speaking, I'd blown it, yet again.   Probably I would have been better off skipping the drugstore sale, buying gas in the neighborhood, avoiding the toll, saving mileage and time (or maybe this would have taken more time -- and it might have ended up costing more in some other way).  And, after all, do I even deserve to feel pleased with myself about the CVS sale when I didn't bite the bullet and buy CVS suntan lotion?

How do people make these kind of calculations? And learn from their experiences in a way that actually might make a difference, moving forward?