You can save yourself a lot of money by purchasing certain cars used in Germany, particularly certain high-end German-made vehicles.
Once you've tracked down your used car in Germany, however, you need to import it into the UK. It's not as simple as driving it through the Chunnel, unfortunately as there's a lot of paperwork to complete and process.
Tell the dealer or seller that you're planning to import the car back to the UK and see if they can help you with the process on the German end. If you're getting the vehicle through a dealership, make sure you understand what sort of warranty will apply, if any.
Pay for the vehicle. Assuming you have a high enough credit limit, the easiest way to this is with your credit card. Alternatively, you can wire the money through your bank, or have your bank draw up a money order.
Sign the required paperwork, and collect your documents. Ensure that you have the certificate of ownership, called the Fahrzeugbrief. You'll want to ensure you have all the vehicles serial numbers, including the chassis number, vehicle identification number and engine number.
Get the vehicle insured for the drive home. If you want, you can shop around for UK insurance at this point and have them provide a green card. You may also be able to get temporary insurance through your dealer. Drive your vehicle back to the UK. Be careful if you're driving a left-hand drive vehicle.
Contact the Driver and Vehicle Licensing Agency (DVLA) and request Form V55/5, which is their document for importing vehicles.
Obtain a European Certificate of Conformity from your vehicle manufacturer. You will need to contact the manufacturer to do this. Some will charge a fee for providing this document, and all will ask you for your vehicle identification number and engine number.
Get a Mutual Recognition Certificate from the Ministry of Transportation (MOT). You'll need to have your speedometer relabeled to miles per hour (MPH), unless it is digital, in which case it can simply be toggled. If your car is a left-hand drive vehicle, you will need to have your headlights modified or replaced to conform with right-hand driving standards. At the MOT, you will need your Certificate of Conformity as well as receipts proving you have made the necessary modifications to your vehicle.
Complete a Form VAT414. You can download it from the Revenues and Customs website. Now compete the Form V55/5 you requested in Step 5. Then go to the DVLA with the following documents: Form V55/5, Form VAT414, MOT Certificate, Certificate of Insurance, registration documents and Fahrzeugbrief and your Photocard License. You will have to pay a fee and purchase a year's worth of registration. The DVLA will mail you your documents in about a week.
Take the documents you received in the mail back to the DVLA to get your UK license plates. Your vehicle is now fully imported into the UK.