In the xkcd comic Working, a man is seen filling up his gas tank. "Why are you going here", says the observer, "Gas is ten cents a gallon cheaper at the station five minutes that way". He responds "Because a penny saved is a penny earned". Randal's pragmatically spirited caption says "If you spend nine minutes of your time to save a dollar, you're working for less than the minimum wage."

Our opportunities to convert time into money and vice versa, though not unlimited, are numerous.

We work (sell our free time) when we…

Seek overtime shifts
Subscribe to a mailing list for local discounts e.g. GroupOn
Bargain with one more car dealer or travel agent, in search of a better deal

We buy free time when we…

Employ cleaners, chefs, babysitters, secretaries and others.
Buy productivity software
Buy a medication that improves our sleep

How can we evaluate these trades? It seems like we ought to only purchase free time when it comes cheaper than a certain figure, $x/hr, and ought to only work if we can sell our free time for more than $x/hr. Indeed, comparing trades to this time/money exchange rate is the only unexploitable way to behave.

Most of the time, when we share our estimates of the value of these trades, our comments are too vague to be helpful. If my father, a doctor tells me, a student, that "subscribing to discount mailing lists is a waste of time", what does he mean? He might mean that these mailing lists are poor value for me, he might mean the much stronger statement that they are poor value for everyone, or the much weaker statement, that they are poor value just for him (his time is obviously worth the most). I have to try to get him to disentangle his estimation from his jugement. I have to ask him "What low value would a person have to place on their time for discount mailing lists to be worthwhile?"

The easiest way for all individuals with different time/money exchange rates to share their estimates will be to quantify them. e.g. being on a discount mailing lists only saves $x per hour spent. Out of my father and I, this might represent value to none, one or both of us.

When we share these quantitative estimates, it would be silly to discuss deals that are only available privately like job offers, that are so dependent on our particular skills and qualification. Instead,we will gain the most by listing time-money trades that are likely to apply across domains, such as repairing a car on the one hand or catching a cab on the other.

By doing so, we stand to learn that many of the trades we have been carrying out have represented poor value, and we should learn of new trades that we had not previously considered. Of course, there are associated costs, like the time spent gathering this information, and the risk of becoming unduly preocuppied with these decisions, but it still seems worth doing.

A last point of order is that it will be best to indicate how far we can expect each estimate to generalise. For example, the cost of something like melatonin will differ between states or between countries, and that is worth mentioning.

So in this thread, please share your estimates in $/hr for potential ways to work or buy free time.