I don't know how you feel about "freemium" type apps, but I personally like that I can get to test out and use a lot of them and just have a choice to upgrade rather than only having the choice between purely free and paid. That said, I've never really paid for an upgrade since most of the upgrades I want are a bit pricey and I don't need the extra features that much quite yet. I'm curious to hear which upgrades our members here have deemed worthy to pay for, though, which I think would say a lot about the quality of the app since you're essentially paying for something you could otherwise use for free - for the most part, that is.
