I'd always recommend doing a proper paint job, but if the car doesn't warrant it, or you dont have the dosh you can do what I did. Its very easy to over capitalise on a VW going doing a paintjob as you end up restoring the whole car!
I painted a beetle back in 97 with a high density roller (you got to make sure its a high density one). Obviously prep your car the best you can, and then you use common house enamel paint, thin it out a bit and then roll it on. Make sure you are in a dust free environment as possible.
Let it dry for as long as you can (a week or more), then use a cutting compound like Farecla G3 finishing off by hand with T-cut or similar. If your arms no longer feel like they are yours you havent polished enough!
The end result wasn't too bad considering it cost 10 pound ($25) and after I left the UK in 97 I sold it to a friend who kept if for years and the paint held up really well.
I have some pics below of the end result, and I have a link describing what I did with a few more pics (excuse the quality they were scanned with a hand scanner in 97!) on an old web page at:-
http://www.geocities.com/matara.geo/bmk208h/vw1200.html
Good luck
Steve