Official Eurail

Train tickets in Europe?
Eurail does not sell single train tickets anymore. is buying a train ticket now the same as an airline ticket. Different prices for exact same trip and type, depending on who you buy it from.
Do you have a good source that you can suggest.
The most confusing to me is that when I try to buy a Frankfurt-Paris ticket from the German railway, I get a price of about 100Euro, when I try to buy the same thing from a French site ( mind you that I have not been able to find the official French railway site), I get prices twice as much.
Here is an official site for the French railways:
http://www.voyages-sncf.com/dynamic/_SvHomePage?_DLG=SvHomePage&_CMD=cmdHomepageUK&WB=HP&rfrr=4685ac17fd2e7656e4918c53b246a3f7
Which ever way you buy your ticket, go for the cheaper option.
But check that is really is the same ticket, for the same kind of train.
Tickets for High speed trains are more expensive, and they have a different price structure to tickets for normal trains.
But often they get you to your destination in half the time so double the price might not be so bad.