I know exactly what you mean; it's always a bit of a gamble with those lower-priced keys. I've bought quite a few games this way over the years, though. For instance, I recently snagged a
Soulmask Steam key from a site called LootBar.gg, and it worked perfectly fine. It's a game I'd been wanting to play, and getting it at a secure and trusted price was a great bonus. I usually check reviews and forums before buying from a new game store to ensure the site's legitimacy and that they offer good customer support.