You don't need a Tivo - just a USB tuner stick and MythTV, or some other open source solution. Granted if the antenna doesn't work then it doesn't work - I had some success buying a powered one.
You don't need Dropbox, just a Linux box and some rsync scripts. $7 is approximately 5 minutes worth of income for a lot of people on here...so if it takes longer than that per month to set up and maintain your solution then it's not a good deal.