Item description:

Turn in the mission to unlock:
New In Town (20G)- Completed the mission "Plan B"

Purchase 1 thing from the Black Market to unlock:
Better Than Money (15G)- Purchased 5 items from the black market

Tip Moxxi $1,000 to unlock:
Sugar Daddy (10G)- Tipped Moxxi $10,000

Start and finish Claptrap's Secret Stash Mission, then after you turn it in give him a highfive to unlock:
Up High, Down Low (15G)- Gave Claptrap a high five

Find Michael Mamoril in any of these 10 locations and unlock:
Near the newsstand in Sanctuary's main plaza
In an alley down the street from the front entrance to Moxxi's
Inside Moxxi's, near the bar
Inside Moxxi's, in the side room across from Sir Hammerlock
In Marcus' weapons shop
Near Claptrap's location, at the end of the street and in front of a building
Inside Scooter's garage, near a stack of tires
Inside Crimson Raider headquarters in the room with Tannis
Inside Zed's clinic
To the left of the door to Crazy Earl's Black Market
Tribute To A Vault Hunter (15G)- Got an item from Michael Mamaril