UPDATE: 14.Sep.2005: Pat's Boutiques in Munich have closed! All of them. The shops still exist. They still sell Dirndls and such. But they are no longer called "Pat's Boutique". More info to follow.
Here is the previous write-up from when they did exist:
If you don't want to spend a huge wad of cash then try Pat's Boutique. This is a chain-store and they have a fair number of the shops in and around Munich (I think there are about 10!). There is one in the city center on Tal beside Sausalito's for instance. There's another close to Hauptbahnhof and a third in Schwabing.
Pat's Boutique sell a lot of second-hand stuff. By "second hand" don't go thinking this means "crusty". Often the second hand items are just factory rejects and not second-hand at all. Most of the items are in excellent shape and you'd never be able to tell the difference between 2nd hand / reject and the brand new gear. When you think about it, you're only going to wear these costumes for 2 weeks a year and spill beer and sausages down them. So why €300 on a dirndl when you can get them at Pat's for €50? Besides, if you're a guy you may actually want to buy used lederhosen so that you do not look like a tourist fresh off the plane.
Eight branches of Pat's Boutique in Munich:
See also: Dirndl shops