BTW, Nothing is easier for a newb than loading Folding@Home's NaCl client in a chrome browser and registering on the folding pool.
My guess is that I would spend way more in internet than I would get in coins. Does anyone know how many megabytes/hour or day is used by folding?
It really depends on your rig, how fast it can process and return work units, and whether the work units are CPU or GPU based.
A dedicated gaming system with a decent GPU for example, might process up to four large jobs per day. New job downloads can be 1-2MB, while an upload (after processing) can be 2-4MB. So worst case that would total about 24MB/day (that's on the high side). Over a month that's about 720MB.
If you are doing CPU-only or NaCl work units on a laptop, the bandwidth requirement is much, MUCH less.
You can search foldingforum.org or boinc.berkeley.edu/dev/ for more specific answers on file size.
I would recommend if you're on a budget, stick with NaCl on FAH or some slow jobs, like rossetta@home on BOINC and meassure how much extra bandwidth they use of a couple days. Then look to buying the coins on exchanges. Currently, few people are making money on GridCoin or CureCoin, so you can pick these coins up at a fraction of what they actually cost most crunchers and folders to produce.