Although it has already been posted that Payday 2 is free to play this weekend
https://www.ozbargain.com.au/node/165700
I think it is more noteworthy that Payday 2 + All DLC's except the newest Hotline Miami are on sale for 75% off.
Prices in USD
Payday 2 $7.49
Hotline Miami $6.99 (full price)
Gage Assault Pack $1.24
Gage Shotgun Pack $1.24
The Big Bank Heist $1.74
Gage Sniper Pack $1.24
Gage Mod Courier $1.24
Gage Weapon Pack #02 $1.24
Gage Weapon Pack #01 $1.24
Armored Transport $1.74
The game is heavily geared towards Co-op Multiplayer, if you want to play solo or offline its probably not the game for you.
All the DLC's are to unlock things like additional weapons & missions. Unlike most other games only the host needs to have the DLC's to play the extra missions.
Don't forget to join the Payday group on Steam and pick up your free copy of Payday 1 while your at it
https://www.ozbargain.com.au/node/154422
Hoxhud is also a great addition to the game and is approved by Overkill so you won't get banned for using it.
https://steamcommunity.com/groups/HoxHud
Enjoy
It's an awesome game. After 15 years I stopped playing CS 1.6 and just play this. pew pew pew.
Good price for the DLC, definitely enhances the game.