In celebration of the release of Crypt of the Necrodancer, maybe, Valve has collected some of Steam's best roguelikes and lopped off much of the cost. The Steam Roguelike Sale runs over the weekend, and discounts roguelikelike heavy hitters like FTL, Rogue Legacy, Risk of Rain and Spelunky, and even a couple of fits-the-rigid-definition-of-a-roguelike, also known as 'proper' roguelikes, too.
My picks of the bunch would be Delver for 50% off, a first-person dungeon crawl with great music; the maybe-too-grindy-but-still-good Rogue Legacy for 75% off; the deeper-than-Moria NEO Scavenger for 33% less; Spelunky for chump change; and the fab One Way Heroics for a ridiculous 77p. You can also grab Binding of Isaac: Rebirth for 33% off, FTL for just under 2, and, well, browse the list yourself, there's a load of great stuff here.
The Steam Roguelike Sale ends Monday 27th April at 10am PST, which my brain always tells me stands for 'PlaneScape Torment'.