I work at a Target and we have Mobil 1 in the 5W-30, 10W-30, and 15W-50 for $3.89 per quart regular price. We also have Pennzoil in 5W-30, 10W-30, and 10W-40 for $1.69 per quart regular price. At our store, we had the Car and Driver brand 5W-30, 10W-30 and 30W on clearance for $.68 per quart.
However, all Target stores do clearance differently. So some stores may have something on clearance that others don't. In short, this could just be at one store.