Count Ferdinand von Zeppelin build the first zeppelin in the early 20th century. Already in 1874 he had outlined the first design of this airship and finished the details in 1893. The next year a committee reviewed his ideas and plans in 1899 granted him patents in the US. The Zeppelin was an instant success.
Before WWI, the DELAG (Deutsche Luftschiffahrts-AG) started the first scheduled zeppelin flights and the Germans made the Zeppelin into a war machine during the war as scouts but also as bombers.
In the 1930s the popularity of the Zeppelin was at its highest and there were even regular flights between Germany, North American and Brazil. Unfortunately, the disaster with the Hindenburg in 1937 started the demise of this airship.
Like most things popular, during the heydays the Zeppelin proved to be very popular as a toy miniature and a lot of toy producers made toy airships, some of them quite sought after nowadays. The difference between a 'blimp' and a 'zeppelin' is that a blimp doesn't have a rigid frame, it deflates completely. A Zeppelin has a frame structure, this can be steel or even some kind of plastic.
What's it worth? Take a look at this Zeppelin price guide: sold listings for a value indication.