Freemium seems all but inevitable, unfortunately... perhaps it can be fair though. If the game starts you off with a reasonable selection of content and $5 gets you enough credit to buy a really decent amount of other stuff players will want that is constantly being added to the game, that's not unreasonable. Maybe other ways to monetize the game like optional subscription fees to have everything available for purchase with bells? Or, as much as we hate them, unobtrusive ads that could even be built in the game with a tongue-in-cheek self awareness like billboards near the shops? Or how about real life products you can purchase for your pad? Yeah, I want an LG 4K TV and Coca-Cola machine for the man-cave.
I'm totally willing to pay for a good mobile experience or deal with unobtrusive advertising, and there must be a way to do it that isn't sleazy like most other titles.