Why the hell cringe? Just ignore the naysayers or cheapskates. If you're a developer, you know how much time and effort it takes to make a good product, right? Take your own independent decisions, after taking all facts and inputs (to a reasonable extent) into consideration.

EDIT:

>naysayers or cheapskates

Didn't mean to imply that your wife was one. The thing is, most non-software people don't know enough about all the work [1] that goes into a custom software app, let alone into a shrink-wrapped product (which is much more, if done well). (Using the old term shrink-wrapped, though a lot of software is delivered over the web these days. Same difference :)

[1] Figuring out requirements / features to include, design, development, testing, testing, testing, ... , support, ... , marketing, ..., maintenance, ...

I sometimes get mails from (not really) customers like: 'can you add feature x of the paid version to the free version?'. The paid version is $4.99 by the way.

If you have decent app that solves problems well and you have enough energy left to do some marketing then probably you can make a decent living. Or you have a lot of luck, then no problems at all. But if you hope that customers find you by themselfes, maybe you shouldn't bet on the business.