Ah, "freemium". I've seen several games out there with the dual-currency model: normal money for day-to-day operations and "special money" for neat things / making things happen faster, a currency that you mostly get by chance.
So you hook the user with variable-reward conditioning and then encourage him to become impatient enough to pay you $$$... No; I'm not really cool with that. Worst gameplay mechanic ever.
I refuse to purchase applications with in-app purchases for this reason, it's not a business model I want to support. Recently dumped "Words with Friends" because Zynga bought them and made it about as scammy as possible. Now happy with Wordfeud.
Nope, I consider that fine. In fact I think paying to make ads go away is a fantastic business model. It doesn't matter if it's a separate app or in-app purchases in my mind.
I've found that there is a segment of people like you who would rather pay for a premium ad free experience up front, and then other people who would not, so I think the point is, if you can have separate versions of the app to address both groups, that tends to work the best.
So you hook the user with variable-reward conditioning and then encourage him to become impatient enough to pay you $$$... No; I'm not really cool with that. Worst gameplay mechanic ever.