Are they good economical cars?
I think you mean Beetle. Beetle is a bug while Beatles are the iconic British rock band.
The original Volkswagen Beetle was a spartan and practical vehicle. Volkswagen after all means "People's Car." Adolf Hitler built the Autobahn to both modernize Germany and as a public works program to reduce unemployment; after all these lovely roads were done few people drove them since cars were rare in Germany and few Germans could afford them. Inspired by Henry Ford's Model T, Hitler asked Ferdinand Porsche to build a car that ordinary Germans could afford. The design was simple and light with a rear air cooled engine and a more streamlined design than most cars of its day allowing the car to travel at high (for it's day) speeds on the new Autobahn. This basic design was produced from 1938 to 2003.
The new Beetle only shares the dome like shape with its predecessor. The original was rear engine rear wheel drive; the new car was front engine front wheel drive. The old car was air cooled the new water cooled. The original was inexpensive while the new one is an expensive car for its size and performance. The new Beetle is basically a VW Golf with a less efficient and less practical body.
The new Beetle isn't a bad car, people buy the new Beetle for nostalgia rather than practicality.
VW Beetle is a pretty cool car. Old fashioned, one may say, but it will all boil down to how you take care of the things you have invested in. It actually doesn't matter if it's a second hand car you are getting or one like the beetle. On top of the things people already gave as an answer, I would add maintenance as a key to keeping your after-purchase costs down. Occasional professional detailing services should be able to keep it good looking and your routine maintenance will keep it in good shape.
Owning a VW beetle is a way of life. It is a car with a lot of history especially the older models. I own a 1964 WV beetle and wouldn't sell her for all the money in the world. So to answer you question Is it a Economical car HELL NO, but buy one HELL YES.
The new 2010 Beetles get about 20mpg. Its not the best, especially compared to some cars like the Toyota Prius, it gets about 51 mpg in the city, or the Honda and Ford Hybrids that get around 45mpg. Even the Jetta gets 30 mpg.