I've been researching altcoins and keep coming across some staggering figures. I think it's just too early to do math, but if I were to farm novacoins for example calculator here and I have pretty much no cost (0 power and 0 hardware), my rig can run 500-600 Mhash/s (aka 500,000-600,000khash/s since that's what the calc uses), lets ignore difficulty increase. The calculator says I can make ~$100 PER DAY. This can't be right, can someone figure out what I'm doing wrong here?
If you already have the hardware and do not pay for your power consumption, then it follows that you would always have 100% profit. If you pay for your own power consumption, you need to be aware that performing mining calculations all day will significantly increase your computer's power usage in comparison to being idle.
I haven't checked the validity of the calculator, but you can calculate your potential mining yield from your mining power and the current difficulty.
Check out this answer on How much Bitcoin will I mine right now with hardware X? for a formula.
Then, it depends on whether it is actually possible to sell the coins that you gained (whether there is a market for it), and whether the above information is acurate, otherwise, it might well be possible to make a good amount of money mining altcoins.