I'm looking for a cheap 50cc retro style scooter. Can anyone advise me on one to buy?

With gas at such high prices getting a vespa is a great investment.
Here are the pros and cons and what you should look for:
The pros are:

Excellent fuel efficiency
Cheap to run and maintain
Cheap insurance
Free parking (if you are careful)
Nippy about town (can weave through stationary traffic)
No licence/simple test required

The cons:
Cannot ride it outside built up areas (too slow)
Dangerous (only protection is what you are wearing)
Easy to steal
No weather protection
Little storage space
Dangerous in bad weather
Cannot take a passenger
They are expensive when new and depreciate quickly If you live in a built up area a 50 cc is ideal. They can manage about 30mph so they are fine as long as you don't take them on ant roads that are faster. In theory cars should slow down for you, and leave plenty of space when over taking but in practice that seldom happens.

You may think this is overkill, but buy all the protective gear (helmet, gloves, jacket and trousers).

Take lessons too before you start out. If you have never ridden before it is daunting and if you get a few lessons at least you will have some road awareness and will be safer.

Hope this is helpful!