It's a convenient starting point, but I'm not sure how well it would perform in practice. Suppose your hourly pay rate is $20/hr. That's your marginal gross benefit of working an extra hour, but your marginal costs of working overtime are probably pretty high -- tacking on another two hours at the end of the workday might mean you have to buy a restaurant meal, take a cab, hire a sitter, etc. It also might just be exhausting enough that you pay an opportunity cost in terms of your ability to accomplish household/personal work in the evening, or even in terms of your ability to properly enjoy whatever entertainment you might have planned. If you have the ability to work additional hours and you don't, we might even say under the doctrine of revealed preference that your marginal costs must exceed your marginal benefits.
And if, in practice, you don't work overtime because it would cost you more than you'd earn, it isn't much use to say that it's "worth" an hour of comparison shopping to save $20. If you skip the shopping and spend an extra $20, you won't choose to work overtime to make up the difference, you'll just buy less of other things or go into debt. Conversely, if you do go comparison shopping, you can probably schedule it at a time when you're least likely to suffer high opportunity/exhaustion costs, whereas you rarely have control over exactly when you work overtime, especially if you have to commute to work and/or deal with the public.
Finally, "deliberation costs" are even fuzzier than information costs -- the problem isn't investing an hour of time in comparing prices, but investing a difficult-to-quantify chunk of your willpower and analytical skills in making a rational decision or in delaying your gratification for an appropriate period of time.
I recently wanted to keep track of my income and expenses, in a cost-sensitive way. I am not very good at treating money as a real object, and very few people are good at valuing an expense appropriately. I'd been having some financial difficulties as a result, so I wanted to be able to reason about what to cut or reallocate in a sensible way. For me, sensible means using intuition instead of hard rules like a computer program.
I took several sheets of grid paper and taped put them together. Using colored markers, I drew in my expenses. If I spent $50 at the grocery store, I would make a blue box that surrounded 50 squares on the grid paper, and label it "Groceries". I color-coded the expenses, but this is optional. I left some white squares representing my savings. I had a whole empty sheet where I could pencil in incoming money as I worked an hourly job to motivate myself (I work from home and need to self-motivate). I realized certain things were a bigger deal than I thought, and other expenses I didn't need to fret about as much as I had been. I think humans are intuitively better at visualizing than dealing with numbers. My main tips for this project are to use a felt-tip marker so the lines really stand out, and to do it by hand instead of computer, so nothing moves around on a "redraw" and you learn the contents as you make it. Also, I used a scale of $1=1 square, but if you have a lot more/less money than me you could use a different scale or omit savings.
I plan to start life-logging and reviewing the use of my time the same way, which is my other exchangable, limited resource, and which I manage even less well.