If you are going to go ahead with it heat go for the 152 or c 152 aerobat if you can find one. the 152 has a 115 hp lycoming o 235 engine with a 2400 hr tbo as opposed to the o 200 continental in the 150 which has a 2000 hr tbo, I would budget around $ 25 000 for engine and prop overhauls. For a hourly with no major problems your looking at around $1200.
The 152 is normally 5 to 10 knots faster in the cruise than the 150 so it's more likely to be used for nav ex's which makes it more desirable.
Also if you have trouble with the old cessna 200 nav com radios that are standard in the 152 don't bother overhauling them (they are valve driven crap not worth spending any money on) you can get a TKM digital nav com that will slot into the 200 series radio mount.
Expect to hire out at $90 to $100 an hour dry - tacho or airswithch