Looking at buying a used Subaru Impreza

[HarrisonO]

Hi there, just need some advice re my first purchase of a Subaru.
I am currently looking at a Subaru Impreza IS 2002 model. The car is a 5 door, station wagon, is an automatic and has 1497cc engine size. I am not much of a car junky, but as I am a student and am looking for a car that will get me to and from places as well as the odd long distance trip(at least 800km).
I am buying it from a site called TradeMe(a buy and sell website). The car is reported as "In great condition and is mechanically sound with no issues. Only a few interior cosmetic damage as expected. Current and previous owners were both females." The Impreza has 158,344km clocked and the cambelt was replaced around the 120,000kms mark. Is there a way I can work out exactly when it was changed cause apparently sticker got removed? The last service was at 147,000km and it was "in great condition." I am looking for a car that is cheap to run(around $75 NZD for a full tank), parts that are relatively cheap if needed to be replaced and is a car that will last me long in the future and I won't have to worry about it breaking down etc. This car is being sold for approximately $3000 NZD, is this right for the facts given? What sort of questions should I ask the seller? AND most importantly will this withstand my needs as I look for a car? Thank you all so much!