LEGO Classic 10" x 10" Baseplate $4.79 at Amazon
Amazon has the LEGO Classic 2304 10" x 10" (25cm x 25cm) Baseplate Large Building Base Accessory (Blue) for $5.99 - $1.20 off coupon (check "Apply coupon" box) =
$4.79 with free shipping on $25+ or with Prime.
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