I'm looking for a 100% free font that is permitted for commercial use that looks like Eurostile Bold Extended: https://www.myfonts.com/fonts/linotype/eurostile/pro-bold-extended-2/

If there aren't any very close fonts, can anyone suggest a bold extended font that has a "retrofuturistic" feel.

It's good, i found one called Waukegan LDO

Fine that you are happy with this copy of the Eurostile. Yet before using it have a close look at each and every character at larger size. Promise: You will be shocked.
When you want to make money make sure that you use the proper materials - including fonts. If I would ever see promotional material from you using your favorite Waukegan, my reaction would be; what rubbish, that company has to be rubbish too. Would you really want those reactions to happen to save a lousy 26 or so US$?

Yes I also have the Eurostile family, it's just the purpose I need it for requires the font to be a commercially free font unfortunately.

Seems you missed the message. Take a close look at that Waukegan ... and shiver.