Check the strings before you buy em.
Some cheapo places sell dull or rusted strings for cheap.
I used to manage a music store once and sold a whole bin of strings for $1.00/ package. I ended up selling about 100 of em until I finally looked at the things and they were rusted through. (The owner of the store was an ass) I tossed the rest out.
Guess I shoulda known the guy was a scammer when half the guitars in the store were 'Huyundai's