I know some may differ on this, but Harbor Freight sells 1/4" size torque wrenches for $10-12 with one of their coupons (not sure of normal price...probably $20-30). I bought a 1/2" torque wrench there years ago, and had a mechanic with a $2xx Snap-On that gets calibrated at least twice a year check some of the bolts on my car against his, and they were within a few pounds at most (these are 60-95 foot-lb).

One thing to be very careful about is ensuring you have proper conversions. Bike components are usually in Newton Meters (N-m) and you'll need to get the correct conversions for your torque wrench. My 1/4" has inch-lbs if I remember right and some other odd measurement...I just got conversions for a few regular torque levels and worked accordingly. Per Google... 1 newton meter =8.85074579 inches pound force