With orders of $25 or more, Amazon offers Prime members the Wonderworld Build A Helicopter, model no. WW-4067, for $5.93 with free shipping. (Non-members can spend $35 or more to qualify for free shipping.) That's $14 off and the lowest total price we could find. It's made from sustainable rubberwood using non-toxic paints, dyes, and lacquers, and formaldehyde free glue.
Note that this item is sold as part of Amazon's "Add-on program" and can only be purchased with an order of $25 or more.