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.