The Patriots subreddit usually puts up streams. Otherwise Google "NFL streams" and the first few sites should have links (one such site that works well is nabwong's scavenger hunt above). Note that the quality is unlikely to be very good, so you'll feel like you're watching a game in the 80s, and you should make sure your antivirus is running because the streams can often try to download malware and other such things. I won't link to them here and get the site in trouble.
If you're going to be outside the US for the entire playoffs, you might look into buying a NFL Game Pass playoffs subscription. It's a good service from NFL.com, but only available outside the US, Canada, and Mexico. In addition, it may be possible to purchase a single week pass for Game Pass.