Dubbed the Innovators Sale, these discounts are primarily offered on indie games, the vast majority of which can be had for less than $10.
There are some fairly recent--and very good--games included, too, such as Videoball for $6 ($7) and Severed on Vita for $9 ($10.49).
This is an incredibly charming and bizarre game in which you explore a post-apocalyptic Tokyo as a variety of animals, including a Pomeranian.
There are many other worthwhile games in the sale; you can see a complete list on the PlayStation Store.
A number of them support Cross-Buy, getting you access on multiple platforms.