How do you get the red bricks in LEGO Batman: Legacy of the Dark Knight?
14 of the 23 red bricks are hidden inside story missions, one per applicable mission. The other 9 are bought from Bat-Mite's Shop in the Batcave for 15k-50k Studs each.
There are 23 red bricks. 14 are mission-hidden — each campaign mission with a red brick contains exactly one, usually behind a side-puzzle (e.g. Filthy Rich via the Iceberg Lounge vault code 596; Toxic Waste using Gordon's Foam Sprayer at ACE Chemicals). The remaining 9 rotate through Bat-Mite's Batcave Shop at prices from 15,000 (Construction) up to 50,000 Studs (Beauty). Each shop brick appears randomly on the central pedestal — re-roll by leaving and re-entering the shop.