@BlurredTheLines
Much belated, but I found the fic in question: Friends With Discounts.

It was AJ. Admit it.

Red In-Apropros.

I’m pretty sure I read a story that went almost exactly like this.

*checks the wallet*  
Darn, only 15 eu… uhh… bits. So no hugs today.
 
This is about hugs, right?

I’ve done a joke like that myself. :D

75% off… It’s a good bargain, Applejack. Granny Smith taught you to take advantage of good bargains, didn’t she? (So what if she also told you not to sleep with mares?)

I knew this was coming eventually… I’m surprised it took this long.

HAAAAAAA! HA HA HA

@BigMax  
well thats just sort of how colloquialisms go. http://en.wikipedia.org/wiki/Colloquialism

@BigMax  
I’ve actually thought of this pun whenever I hear this phrase worded this way. :D

@Lawful Girly  
I totally understand that.  
In my country, there’s plenty of dialects and vernaculars.  
It’s just that I don’t know many of these English local forms :I

@BigMax  
Yeah, I’m a huge Grammar Nazi myself, but I understand this one–it’s dialect, used most often by people trying to be folksy and friendly, such as Southerners playing to the stereotype (like Applejack) and obnoxious used-car salesmen.

@BigMax  
Well, it’s OK. It might technically be incorrect to say “What can I do you for?”, but people really do sometimes talk like that.

@ein-kerl  
I don’t know, I’m not from the US, and English isn’t even my first language. :I  
So that’s why my brain bleeds every time I see some grammar disasters that even a weak English speaker like me would never make.

I lol’d

@Hellfire  
One bit=all your tears.

@BigMax  
It’s a dialectical choice, I think.

That’s right Twilight! Appeal to her thrifty side!

Wow, that took me a while X3

And that’s why you say “what can I do for you?” instead of “what can I do you for?”
 
Seriously, it took me a while to find the error that caused the joke.

more of an RDxAJ fan but…buck it! take the deal AJ!!!!!!!!!!!!!!!!!!!!!

someone is desperate for that apple juice

That’s a good deal.