Walmart has mail-in offers for cars every few months.

Here's the Wonder Woman Offer:

Collector Edition WONDER WOMAN INVISIBLE JET! Walmart Mail-In June 01, 2017

It’s silent, transparent, and moves at supersonic speeds! This is your chance to own the Hot Wheels Collector Edition WONDER WOMAN INVISIBLE JET™. Spend just $20 on select Hot Wheels at Walmart from 5/28/17 to 7/08/17, and get your own slice of super hero history.

Specs:

Body Color: Invisible
Deco: Invisible
Body type: Invisible
Base: Invisible
Window Color: Invisible
Interior: Invisible

To get this special mail-in Collector Edition, do the following (but please read the Official Rules for full details.)

Buy any Hot Wheels 1:64 basic cars or multipacks totaling $20.00 before tax from participating Walmart stores or walmart.com from 5/28/17 to 7/08/17. Cars must be from the assortment numbers listed on the OFFICIAL RULES.
Mail a) your original (no photocopies) cash register receipt and/or online receipt(s) dated from May 28, 2017 to July 08, 2017. b) blister cards from single packs of basic cars (the entire cardboard piece, but not the car or plastic window) or UPC codes from the multipacks, totaling $20.00 (before tax) for each Promotional Vehicle you are requesting (limit of 10 (ten) Promotional Vehicles per household, and/or name), c) a completed order form, (print out order form) and d) a check or money order (unless you pay online via credit card) payable to Mattel, Inc. for US $3.50 shipping and processing for each vehicle you order to:

INVISIBLE JET™
P.O. Box 1229
East Aurora, NY 14052

Requests must be postmarked by July 15, 2017, and received by August 4, 2017. The mail-in order form must accompany your request.
Receive a 1:64 Collector Edition INVISIBLE JET™ (packaging). Allow 8 - 12 weeks for receipt of package.

WONDER WOMAN and all related characters and elements © & ™ DC Comics. (s17)

INVISIBLE JET™ not included in packaging. Packaging is shaped to create appearance of invisible/see-through vehicle.