I don't think you'll get much for £5000. Most pick-ups in this price range will be 10+ years old with sky-high mileages. It will be a case of 'when' and not 'if' something expensive goes wrong. If you're looking for a cheap pick-up to run into the ground then a 13 or 14-year-old Ford Ranger might serve you for a year or two at this price range. But the fuel and maintenance costs will be high.