Deleted

Are you trying to make a fake website that makes you look credible for some nefarious purpose? :P

If you're a student (or still have access to a .edu email address), check out https://nc.me/ for free .me, or discounted .com/others.

Some webhosts used to give you a free TLD with their hosting plan. That's usually the most expensive part of a website anyway though.

.com SHOULD only be commercial sights as that's what com is short for. alas no one respects the abbreviations any more.

If you believe in your product then buy a domain.
If your product has zero potential to make you money but you still want to get it out there then just get one of those .tks or any other TLD's, heck you could even get a free .blogspot or .wordpress site.
In the end though, you should post a lot on facebook (Make a page for your product) and other social platforms list reddit, etc.
If it's free, it doesn't need it's own personal domain until you decide to start earning with it and by then you will be comfortable purchasing a .com