A group of seven games highly praised by the Steam community are available for cheap as part of the Humble Very Positive Bundle 3.
Featuring a range of diverse and interesting titles worth over 100, you can be sure you'll find something of quality here based on the recommendations of other players. In fairness, if I only got the phenomenal Nex Machina for less than 10 I'd be more than thrilled!
Before I get too far ahead of myself, though, let's start at the first tier. The Humble Very Positive Bundle 3 starts at just 80p for psychological horror Distraint 2, tough roguelite Unexplored and atmospheric point-and-click adventure Rusty Lake Paradise. I've not seen much of these three games myself, but for less than a quid I'm willing to give them a go.