Interesting observation. I’ve been noticing this too but hadn’t really put my finger on it until you mentioned it. My guess is that Autocheck is undercutting Carfax in an attempt to gain market share – and it seems to be working.
When I’m seriously looking for a car, I’ll use Autocheck to vet cars initially since they have deals like 25 reports for $50. But since Autocheck doesn’t really have any service history info (which is pretty important to me), when I find something I’m really serious about, then I’ll spring for the Carfax report. Even though Carfax is way more money (6 for $100), the extra information is worth it.
One recent discovery I’ve made is that Carfax actually has a decent amount of used car listings on their site, and not only do all of them come with a free Carfax report, you can even filter the results by vehicle history details like one owner, no accident history, and available service records. Of course, all of the listings are dealership cars, so it’s not great if you want to buy from a private party. But if you don’t mind buying from a dealership, it’s super handy to narrow down a list to just the very best examples (at least according to their Carfax histories).