Today I was at Toys R Us and I found a winter-themed Pinkie Pie with a cape in a package that said it was Minty, not Pinkie Pie.
Is this mistake worth anything?
I don't know either. I've got a ponyville Pinkie Pie with rollerskates set, but no rollerskates in the box. I doubt it's worth more than the current value of that pony at the moment.
I think this is something you would have to hang onto for a long time before it becomes worth something - nice find though, probably is worth picking it up