Where you shop for your used motor depends mainly on how lazy you are. The more effort you put in, the more you can save.
Buying from a dealer, for example, is low hassle but prices are higher. Go to an auction instead and you'll more likely bag a bargain.
Here are your options in detail:
Buying privately is generally cheapest, but beware of over-optimistic pricing from greedy sellers. They won't give the same back up as a dealer. And just because they give you a nice cuppa, don't be put off asking awkward questions
Franchised dealers usually have the newer cars in stock, which will often be better cared for and have lower mileages. The downside is they also charge the most in general
Independent dealers have long since shed the sheepskin coat and most offer the same facilities and experience as a franchised dealer. Cars here may have a few more miles under their bumper, but expect good quality service and cars as independent dealers live by their reputations. They're also more likely to be open to haggling than franchised dealers
Car supermarkets rely on quick turnover. This means their prices are lower than other types of dealer, but there's little room for haggling. Their stock can vary in age, but it's mostly cars up to three-years old and will be made up from mainstream models, so not the best places to look for unusual choices
Don't forget auctions. These automotive parades offer rock bottom prices, but it's easy to get carried away. If you know what to look for, have done your research and are confident of the car, a bargain awaits. Otherwise, it's possibly better to shop elsewhere.