I make about $10k a month with a one person saas. Self taught via YouTube and stackoverflow. Sales background career wise, although I was a Basic/VB nerd as a kid.

Php, jQuery, running as a SPA technically with php server side rending the html I have jquery squeeze into whatever div makes sense.

Runs on a $4 a month namecheap server, only because I ran into a stupid limitation on the $2 server.

Faster than most modern SPAs or websites you find on the internet.