Ok so before you guys freak out, this is just what I would want as a post-credit scene for Age of Ultron.
So it starts off in Tony Stark's office conducting an interview. He says, "Very impressive resume, I could use a guy of your talents, but there is one problem. Your criminal record."
You hear a voice but the screen still faces Tony Stark, "I am aware of that sir. It was all just petty theft and my daughter was ill. Desperate times call for desperate measure, but I know that's not an excuse and I bet you don't wanna-"
Tony cuts him off, "As far as I'm concerned, you served your time and now your here trying to make an honest life. And FYI, any father in your situation would do the same thing. I would now like to congratulate you. Welcome to Stark Industries Mr. Lang."
Screen goes to Paul Rudd as Scott Lang, happy saying, "Thank very much Mr. Stark, believe me you won't regret your decision."
"You gotta promise me however, no more stealing."
"That is all behind me Mr. Stark, never again." Lang says that with a little smirk.
End of scene.
To those who read the comics, Scott Lang actually worked for Stark Industries and helped Tony Stark install a new security system in Avenger's Mansion.