I used widgetlocker in the past to customize my lockscreen. It's a paid app.. and I bought it so long ago I don't remember how much lol..
If you want to go the free route, I believe there's a GoLocker also that's free
AT&T Galaxy S5 running stock rooted until some ROMs come out
Nexus 7 2013 Edition stock
Original Kindle Fire running CM10
Android History:T-mobile: Motorola Cliq ran CM7 --> HTC Amaze ran CM9 --> AT&T: Samsung Galaxy S3 tried just about every ROM on this site