Help, I need to buy a torque wrench

I want to be able to start torquing bolts to correct specs and my buddy with complete Sanp-On truck moved away so I need my own.

Checked out Sears and they have 3/8 clickable for $80 up to 1/2 digital for $250 or so.


Are clickables more accurate or reliable than manual/gauge ones?

I will be using this for head bolts and valve cover bolts.
Is 3/8 good for this work or is 1/2 better? All my sockets now are 3/8.

Thx