EA Promo weekend with 60-85% discounts on some good old retro games like:
Sid Meier's Alpha Centauri
Sim City 2000
Populous (various editions)
(all down to £1.89)
Some slightly newer ones including Medal of Honor (now £3.09), Nox (now £1.89) and Sim City 4 (now £6.19)
All are DRM free and have a money back guarantee if games dont work etc.
Some good old titles on there (see link for full list), they might not have the graphics of No Man's Sky...(no comment) but they are very playable for the price of a coffee!