you would be hard pressed to find concrete for 100$ a yard. I would think 150$ would be more like it. I would use number 3 or 4 rebar at two foot spacing with a two foot over lap. chair them up with 1.5 inch patio pavers as to keep rebar elevated while placing. saw cut the floor 1/3 depth of the concrete. Say 10ft by 7.5ft if just doing end of shop. After slab is sawed soak down with water and cover with poly, reapply water to keep wet. leave poly on for 7 days. let dry and apply a good sealer. brock white has a number of them. best of luck.