Best basal thermometer?

Hi all! TTC first child. I just started using Glow to track everything and thank God because my cycle decided to switch on me this month. I've only been off birth control since Sept/Oct, and I think my body is still adjusting (I should've gotten off bc a long time ago...)
​Anyway, I think I'd like to start tracking my temp but I don't know which thermometer is best for this. Suggestions? Thank you!!