I agree whole-heartedly with 40hz in that if you can afford it at all, support any freeware developers whose software you use regularly. I always do; always have. I understand that I have been very fortunate to be able to donate, and that some cannot do so. Well, they cannot do so at least for a time. But everyone usually has good periods when they have a regular income; hopefully most are fair about donating.
What I imagine can get very frustrating for developers of free application is that a lot of folks demand that their software stay free, and further demand that they constantly work on bug fixes and adding the features they want. I mean, greedy to a very large fault! If you don't think it is that tough, take a look over at LifeHacker or even "Give Away Of The Day"! GAOTD had a media file converter available today and you have to read the comments there - apparently the software does not yet support Vista. The user comments there are extremely bitter because of that, even though the developer posted that Vista support would be available shortly. You would think this company was run by serial killers or something from the user reactions! "Rotten", "cheating", "idiot" are just some of the terms used. Hey, if they really want everything exactly as they like it they could purchase any number of converters that are out there on the commercial market! But they would rather hurl hateful crap at that developer.
And at LifeHacker whenever they run a poll of the Five Best {Name the utility app here}, free programs are always the overwhelming choices for the top spots. As if "Free" must equal "Best" rather than "What I want". Some commenters at LifeHacker have actually "scolded" Gina Trapiani there for daring to post reviews of "PAY" applications.
If I were a developer of freeware, it wouldn't take a whole lot of that kind of "respect" by the users to convince me to go commercial!
Jim