Had to pick between a $12 dotted notebook and a $40 official bullet journal for my new system.
I went with the cheaper one and honestly, after six months, the paper quality is fine and I'm just glad I didn't overthink it, so what's the most you've spent on a notebook that actually worked for you?
Have you tried a simple spiral bound notebook with dividers? I use a $10 one from the drugstore and it keeps me just as organized. The trick for me was using a pencil case with colored pens to color code tasks. Maybe the real secret is just finding what you actually stick with using.