For in-store pickup only, and with stock and pricing varying by ZIP code, Home Depot offers the 8-Foot Pressure-Treated Landscape Timber, model no. 129430, for $1.97. That's tied with our mention from last May and the best price we've seen. (It's a current low by a buck.) It measures 2.75" x 2.5".

Note that this price may not be available in all ZIP codes.