There are a few people around who do cheap car "rental". However, what they actually do is to write out a contract for you to buy the car at €xxx per mth/qtr. This is to cover both parties in the event of a police check. After the rental period they just take back the car and the paperwork.
Such cars on not very good, but what would you expect? In addition, whilst you are 'hiring' the car, you will become liable for non-insurable problems, e.g. punctures.
It's done as a tax fiddle of course. €280 though, for a small car for a month is a very good deal, particularly so if it is a genuine 'car hire'. I can point you to one that is advertised for €250 per month if you want, but personally I wouldn't drive it as far as I can spit.