Data analyst UK reading material recommend

Hello, I'm a data analyst based in the UK. I am able to read SQL and JS for Appscripts and can write basic stuff.

My primary platforms at the moment are Qlik Sense and google sheets.

I'm looking to expand my knowledge by reading for an hour an evening. After I finish 30 minutes of sql puzzles to learn from. When I feel proficient enough I'll be starting my own projects.

Can you recommend some books that are cheap as I don't have much to spend on material.

Thanks!