Besides the six dollar VPS, and the fact that if you do not have six dollars available for having a VPS, which means default PC staying on forever, there runs the risk of DDoS from any individual who deems your server a target for whatever reason.
Six dollar VPS' rarely defend against a DDoS attempt, so be ware if you have someone who dislikes you and knows how to do that.
There isn't a way to fully keep your server running without a VPS, or keeping your computer on.
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The place to be is home.