I already have a PC that can handle doubling as a HTPC, so my only cost is really for the Ceton card, and to run ethernet if wireless isn't going to cut it.

So I'm looking at $400-500 instead of $10/mo.

This is one of the same reasons I'm considering OOMA. $200 to get free phone service vs. ~$25 a month Vonage is up to now.