I also have a Harbor Freight 1/4" drive torque wrench that I got for about the same price.
IMO, the calibration on it is a bit off so I allow for the error by adding a correction number to the setting I'm trying to set.
To explain what I'm talking about, I keep the knurled torque adjustment sleeve with the numbers on it is kept fully "unscrewed" below zero. This keeps the wrench from putting a load on the spring while the wrench is sitting in my tool box.
When I want to set the wrench to some torque value, I screw this adjustment sleeve clockwise to set the torque I'm looking for but I notice the sleeve turns past the "0" mark and it doesn't start to show any resistance to being turned until the reading gets to 5. (Yours will probably be a different value. If your real lucky, it will start to show resistance at "0".)
Knowing that the tension on the internal spring is what determines the amount of torque the wrench is set to, I add 5 to the value I want.
For instance, if I'm tightening the small hex bolts that hold the oil filter cover on, the Shop Manual says it should be 4 lb/ft.
4 lb/ft = 12 X 4 = 48 lb/in or 48 inch pounds as we say in America.
Adding 5 to the 48 I get 53 inch pounds so that is what I set the wrench to. (Don't forget to tighten the lock screw at the bottom of the handle after setting the torque value.)
Most of the better quality torque wrenches make a nice audibly "click" when the torque value is reached but my Harbor Freight wrench doesn't make much, if any sound.
Knowing this, I carefully watch the area where the handle reaches the ratchet head. When the wrench reaches the torque value, there is a noticeably movement between the handle and the head that tells me I've reached the torque I want.