How to buy a cheap vacation?

Hi,
I am from the Czech Republic and I would like to go on a vacation to the seaside this summer. I am considering travelling to Germany (probably the closest would be Dresden, I might even go to München or Berlin or Frankfurt) or Vienna to buy my vacation right there, at the airport. Could you please tell me how cheap these vacations can get? How wide is the range offered? Do travel agencies sell them for even less then advertised on the internet? Do you have any experience with this?

Check out http://www.myshoppinggenie.com/cheapstuff this should be exactly what you are looking for! it is a FREE application you can download for your browser and it basically searches the WHOLE internet for the cheapest price for the product you are looking to buy.