I was unemployed in 2018 and paid no taxes. Turbotax calculated $150 tax return for my provincial part (I'm in BC). I didn't see it and submitted online. What do I do?

Have a look at the PDF copy of your filed return, specifically the Form BC479. It sounds like the $75 Sales Tax credit that BC residents are eligible to claim. If you have a spouse, that would explain the $150.

The BC forms will tell the tale!