buying 2006 legacy wagon 3.0r

[InfinX]

Im looking at buying a 2006 subaru legacy ez30 it has just over 180 thousand ks its in good condition. What are the main things i should be looking for and asking to make sure its okay. Its at a very good price about 30% under average price the guy said the timing chain tensioner is worn out and is making a whining sound and would be about 300$ to fix, does that sound right apart from that what else should i looking out for before buying?