Since you’re open to paying, have a look around the video descriptions of channels like Wendover and HAI, they often have promo links to get nebula for around ~$25-35 for the year, works out to just under $3 per month.
I’m not aware of anywhere that pirates Nebula content, although I’m aware that floatplane (similar but less popular platform) used to get pirated to YouTube on a regular basis a looooong time ago