If you've ever searched the web for a Free Vin Check to check your car Vehicle Vin Number History Report, You Know that 99% of Free Vin Checks are just scams to get you to buy a vehicle history report.
Since 99% of free vin check reports are scams, Are there any real, legitimate, Totally Free Vin Check Reports?
After reviewing HUNDREDS (if not thousands) of alleged "FREE VIN CHECK" websites, I can safely conclude that Yes, there ARE in fact, real, totally free Vin Check Report sites on the internet, but they are rare, and usually NOT legal; In these rare cases, more likely than not, a person will buy an unlimited account and set it up to run "Free Vin Check Reports" for people, usually in exchange for the visitors clicking on Ads.
By doing this, not only is the person providing the Free Vin Check Reports violating Google Adsense's Terms of Service, but also more than likely, he/she is violating the terms of service with the company that they're getting the Free Vin Check From.
So Would you suggest that we use these Free Vin Check Sites?
Judging by the fact that you're looking into buying a car (why else would you need a free vin check?), I would say that you're a responsible adult that (more-or-less) knows the risks associated with buying cars, if not, check this vehicle-buyer car buying tips blog for a list of some pretty basic and useful information on buying cars.
And since you're an adult that knows the risks of buying used cars, then you probably know the risks associated with getting a FREE vin check report; You have no guarantee that the information you're paying for is true! Unlike a PAID vin check report, it is my experience that some free vin check reports (from the less-reputable companies) are not 100% accurate.
So what would you suggest instead of a Free Vin Check Report? Carfax is too expensive!
Yes, Carfax is a ripoff. The reason that CarFax charges so much for their reports is because Carfax spends quite a bit on advertising, my educated guess is that CarFax spends over 75% of their profit on advertising!
The alternative to Carfax? I Suggest a Cheap Vin Check Report:
This $10 Vin Check Report that gets you the same information as Carfax Report?
Yes. This company barely spends any money on advertising, and the only way I found it is because a friend (who owns a dealership) actually heard that I was reviewing Free Vin Check Companies and told me about this company, so I ordered a $10 Vin Check from them to try it out. Sure enough, Same Information as a CarFax and AutoCheck report, just in a slightly different format! AMAZING!
Will this $10 Vin Check Report Last Forever?
What kind of question is that?! I'm not a wizard (But i'm working on it!) and I can't predict the future. But I sure can tell you; If you're looking to buy a car, why wait a week to get a Free Vin Check when you can order a $10 Vin Check? Again, This report was $10 when I wrote this article, I talked to the owner and he said they might have to raise prices a little, due to demand increasing and the company had to hire on more staff to deal with the extra load, but I don't know, and do not plan on waiting to find out 
I got Vin Checks for both of my cars, in case I decide to ever sell them; I can offer the Vin Check Report for Free to the potential buyers, and will refer them to the $10 Vin Check site as well.