The pillar of the 145 community...
1. Check the belts/variator have been done.
2. Check them again.
3. All the usual as with any car, oil filler - no white gunk (a little is acceptable if it's been used for short runs), no abnormal knocking from the engine, check no blue smoke, or generally smoke on the overrun.
4. 145's tend to eat front wishbones, look for signs of uneven wear on the front tyres.
5. Face lift or not? Facelifted models have a different grille and front/rear bumpers, along with a different engine (155bhp compared to 150bhp). The newer ones have a plastic engine cover, the old ones are alloy. The changeover was 1999 I think, but there are a few non-facelift cars with the newer engine.
6. Take it for a drive and enjoy it, there's not much that can go wrong if they're well looked after.
145's are a surprisingly well built car. Alfa needed to up their image a bit after the debacle that was the early 90's. They engineered the 145 very well.
I'd say a fair price, depending on condition, age and mileage obviously, for a non-facelift Cloverleaf would be about £2200.
Facelift versions tend to be a touch higher, from maybe £2500 upwards.
Let us know how you get on.