Re: As a niche device owner....
It all depends on the value provided by what you get in the first place:
I have two tablet gaming apps, Battle Academy and Total War, $19.99 and $9.99 respectively. These are extremely fun wargames "out of the box". Battle Academy sells you extra scenarios, Total War sells you XP and sundry. I might buy scenarios, but never XPs. I agree with Battle Academy's model, Total War leaves a bad taste.
Still, why should I care? I can take it or leave the in-apps, but both games are well worth their initial $*.
On the flip side, I installed "Master Your DSLR", a $0 camera manual app that is supposed to tell you how to use your DSLR. At $30 a pop per model guide, with not even a sample model's manual provided. They have a good reason not to provide samples - apparently the manuals suck, once paid for.
This is blatant ripoff-ware, I reviewed it as such and so have many others. Many thanks to the photo enthusiast website that recommended it.
In-game purchases are the same as ads. Most of the time, thanks to other folks' stupidity generosity, I can get stuff for lower prices. Some of the time, the cost is justified to subscribe to extra content that would otherwise not be economical for the developer to provide.
Well-done it's a freemium/premium approach, not a gouge. Badly done, it gets negative reviews. Either way, you're not obliged to pay and app stores should have child-proofing mechanisms in place (courtesy Apple's rather expensive legal loss in that domain).
What's y'all's suggestion? Regulate it out of existence?
* seem expensive? My metric is how many hours of entertainment/$. Both were well worth it. Much better value in any case than a $10 movie with $6 popcorn. Or $29.99 Nintendo DS games. Not quite as good as Netflix $7.99/mo.