Amazon has Lego 405-piece Ultimate Building Set for $19.97. Shipping is Free with Amazon Prime or if you spend $25 or more.
Alternatively, Walmart has it for $19.97 as well. Select free site-to-store shipping, otherwise it's $0.97 to ship to home.
Next lowest on Google Products from a reputable store other than the ones listed above is $25 shipped.
This is one I think the Bug will see under the Christmas Tree.