Preferably lesser known but game-changing apps that are able to be bought one-time and put all others to shame.
To help clarify your thinking, which apps have produced such an outrageous level of value (regardless of one-time cost) to the extent you believe it should be #1 in its category, not necessarily #1 app ever.
We’ll do a seperate thread for Mac, Windows, Linux, Android, etc but let’s stick to iOS for this one. Thanks Lemmings!
I wrote it to automate my workflow - I’m in sales. I enter site details at the customer location and my app crunches the numbers to pre-fill all relevant documents (contract, financing, etc) in PDF form. I also use it as a presentation device to explain service and product details/specs using pictures, videos and PDF documents.
No more paper, no more fiddling around with calculator and rate-cards. I do a little data entry and basically my job is done.