There are any number of reasons not to spend the money. One is that I have downloaded literally hundreds of programs over the last couple of years, and if I paid even $10 each for them, I'd be broke. I do a lot of stuff on the computer--I'm on it 10 or more hours a day, every day. A program that gets used for 10 minutes a month isn't worth that kind of money. And often, when I DO pay for a program, I end up finding that it either doesn't do everything I need, or that there is a better freeware version available (like the star office version which is superior to NXPowerLite in interface and options, only it doesn't work for M$).
Second, I would always rather use free and/or open source software, and I'd rather pay someone here at DC $5 or $10 in credits and have it available to the world. Plus, if I get someone here to do it, I can ask for specific features and get the warm fuzzy feeling that comes from beta-testing.
Third, I would use this mainly for work. I'm technically prohibited from installing ANY software on my machine (or even plugging in a USB drive, for that matter). But my IT people are pretty cool and won't hassle me as long as I don't screw anything up on the network. Still, there's not a snowball's chance in hell that I'd ever be given approval to buy non-authorized software. And the only reason I use this is because our IT people have arbitrarily capped our email storage limits to about 450 mb, so I'm just saving my workplace money in storage anyway and saving my coworkers the hassle of having to constantly go back and delete these big files.
And no, I most definitely would NOT pay someone $4 or $5 to do this for me. I just wouldn't do it at all, network storage limits be damned. That's what I do now (er, don't do, I guess).