You will eventually be caught, perhaps arrested, fined, jailed, banned from Walmart for life (the horror), and have a criminal record, regardless of why you stole, what you stole, whether you gave it back, and whether you feel sorry.
As @shipwreck says, you could (in theory) be "locked up" until you're 18, or if you continue doing this when you're 15, you could be "tried as an adult" and die in prison.
If they don't press charges or give you something in writing then nothing.Most of the crap at Walmart I wouldn't want if it was free,
Yes, they will come get you and lock you up until you are 18. Saying you are sorry after a crime isn't good enough.
Stop doing this ya ijit!!
js