I bet you could do it if your instance didn't pull in a lot of traffic.

If it did..... I reckon that you might be able to pull it off to a certain extent so long as your internet package was good enough, but if you got hit with a Reddit-level flood of incoming users, your network almost certainly wouldn't be able to keep up.

Even if it could, if you were consistently eating through all the upload bandwidth, I reckon you'd draw the eyes of your ISP and they might send you a letter kindly and respectfully telling you that if you don't upgrade to a commercial line they're not renewing your contract.