The classic game Deus Ex: Game of the Year Edition (90/100 metascore) is on sale for $2.48 at GMG. I believe this deal expires today. If you pre-order the latest game Deus Ex: Human Revolution you can get Deus Ex: GOTY for free. If you use the voucher code FACEB-JULY3-20PEC you get Human Revolution + DE:GOTY for $28.80 and because HR uses Steamworks you can activate the game on Steam.
Make sure to pay with or through Paypal to avoid foreign transaction fees.