It looks like Google has surreptitiously started a little summer promo in the Play Store with discounts on apps and games, with some going below the usual $0.99 barrier. There's no official landing page yet, so we don't know everything that's included, but more could still be on the way.
Apps
Beautiful Widgets – $0.99 from 2.75
Bright Weather – $0.99 from $2.79 (in-app purchase)
Asteroids Pack LWP – $0.99 from $1.95 (spotted yesterday)
Galaxy Pack LWP – $0.99 from $1.95 (spotted yesterday)
Games
Reaper – 50% off in-app pro upgrades ($1.50-2.50)
Blueprint 3D – $0.75 from $1.50
Iron Force – 30% off select in-app purchases
Monopoly Millionaire – $0.50 from $0.99
The Sims – 50% off select in-app purchases
NBA Jam – $0.99 from $4.99
Sprinkle Islands – $0.99 from $1.99
Tetris Blitz – 50% off select in-app purchases
Dead Space – $1.99 from $7.99
Theme Park – 40% off select in-app purchases
Little Big Adventure – $1.99 from $4.99 (spotted yesterday)
Update 7/24/14:
Striker Soccer London – 50% off select in-app purchases
Train Crisis HD – 50% off select in-app purchases
Striker Soccer Euro 2012 Pro – $1.33 from $2.99
Swipe Basketball 3D –50% off select in-app purchases
Mines of Mars – $1.99 from $3.99
These are only the titles that are listing a connection to the summer sale. There are other (presumably unrelated) sales going on that we'll get to later. This post will be updated with any more summer promos we spot.