Buying cheap can sometimes be a false economy.
If you intend to ride all year then you need to keep on top of maintenance or get single speed (if route is flat) or an Alfine type system.
As others have said, mudguard clearance is a good idea. Mudguards for frames that aren't designed for mudguards are always a comprimise.
My commuter (for a flat commute) is a fixed gear bike with mudguard clearance (and eyes). Just have to oil the chain and change tyres/brake blocks.
