Amazon offers LEGO Creator Space Shuttle Explorer for $20.99 with free shipping via Prime. (Target charges the same with pickup.) That's tied with our mention from two weeks ago and the lowest price we could find by $9. This 285-piece set can be rebuilt to make a Moon Station or Space Rover, as well as the Space Shuttle.

Update: It's now out of stock at Amazon; however, Target still offers it for the same price with in-store pickup.