Prices stop being abstract when you see them as time. Enter your pay and a price.
The calculator turns your monthly take-home pay into a true hourly rate, counting only the weeks you actually work, then divides the price by it. The result is how many working hours, and roughly how many working days, that purchase costs you.
This is a perspective tool, not a verdict. Some things are worth ten hours and some are not worth one, and only you can say which is which. What it does is replace an abstract number with something you can feel, before you decide.