3 COUNTIES CAR SALES LTD, Great Deals On Used Cars In BEDS, BUCKS, NORTHANTS. If you are looking for great savings on quality used cars in the beds bucks and northants area , then you have reached the right place. 3 COUNTIES CAR SALES LTD are a specialist used car dealer based in Buckinghamshire . We are proud to offer you a first class customer service and very competitive pricing, so please browse our stock list. At 3 COUNTIES CAR SALES LTD we stock a range of used cars to suit all budgets and lifestyles so we are sure to have the right car for you.