It is often extraordinarily difficult to usefully quantify the value that you get out of money spent. Say you spend $20 to go out for dinner with friends. At a minimum, hopefully you aren't hungry anymore. Maybe there's some dollar value that you could assign for the time spent with friends. Maybe they'll mention a book that you read because of one of their comments, adding to the value. I suppose in a best case scenario they bring someone with them who you end up being friends with. Putting a number on that is all very difficult, and there's not usually much point in it.
It might be more feasible to put a value on possessions you purchased, but even then the
stuff that has lasted the longest and proved the most valuable may have been acquired so long ago that actual prices can't be remembered with any precision.
To simplify matters, I'm going to cut it down to $1. There aren't too many things that can be purchased for a dollar, and fewer still that can be used over and over and accrue significant usage value beyond the purchase cost.
Based on that criteria, I feel comfortable saying that the best $1 I spent was for a black metal water bottle I bought from a fellow radio station staff member at her garage sale that she held in conjunction with her Kentucky Derby party one year. I don't recall how many years ago this was but it was post-divorce and pre-M so at least 5 seems right. Whatever the interval was, since I acquired it that water bottle has gone with me to the radio station every Sunday through the end of 2017, when it was replaced by a water bottle my coworkers got me as a birthday gift. It's been to every session of
CrossFit I've ever attended. It's been my water bottle in the car on numerous road trips and on quite a few hikes. At a rough estimate I've used it at least 500 times, which isn't too shabby for a $1. You could add in some more value from money not spent on bottled water or other beverages because I had a water bottle with me. For example, I used to buy pop at the radio station most Sundays, and I haven't since I got this bottle. There's probably some health value to drinking water instead of less health beverages, and I suppose some societal value from less pollution and consumption as well. Not bad for $1.
The bottle is pretty dented up from being dropped, and I expect that one day it will be sufficiently damaged as to be unusable. I won't have any complaints then, as I've already gotten value far out of proportion to the $1 I spent on it.