The BBB *is* a scam.
Over the years, I have seen several reports, on American websites, suggesting that the Better Business Bureau is rather dodgy. Typically, the allegation is that they will let anyone join, on payment of a fee. So the BBB logo on a web page is pretty meaningless. All you can be sure it means is that the company using the logo han't been caught.
But the BBB is a sort of franchise organisation. Read the blog post below, but remember that the problems implied by the examples may be limited to a few places and times.
Deciding who to trust is hard.