Amazon offers Performance Tools 3/8" Drive Ratcheting Adapter for  (Reg $10) +Eligible for Free Super Saver Shipping.

Note: Clip the extra coupon on the product page 

Product Description:
Converts any breaker bar or sliding T-handle into a ratchet. Hex bolster for use with an open end or adjustable wrench. Works independently as a thumbwheel ratchet. Heavy duty chrome vanadium construction. Oil resistant black phosphate finish. Maximum torque: 164.5ft/lbs (223Nm).