Or pickpocket all their money, and convince them you didn't do it (I kept seeing Target roll of 1 for this.... sooo.....)
Just steal weapons you need ezpz. 
Smith be liek 
- "Help a thief! That weapon you are brandishing with my initials - T.F. wtf I did not sell it." 
and you are 
- "[Persuasion] Nah mate, I got it in Baldur's Gate from a smith named Toyota Ferrari, just a coincidence."
- "Alrightey then, makes sense. Better be careful there are thieves here!"