Toll roads in Germany, Czech Republic
 

Directions on Yahoo Maps indicate several toll roads between Berlin and Prague. Do we need exact change? Will the rental car place (Hertz) have stickers or passes?

There is no toll road in Germany - other than some private roads in the Bavarian Alps. All German Autobahns are free (for cars).
In Czech Republic, you must buy a toll sticker to drive on motorways. Valid for 7 days, 1 month or a year, they can be bought at border points, gas stations, post offices etc. See http://www.czech.cz/en/czech-republi...orways-network
You need to check on renting a car whether it already has a valid sticker, and if not, you have to buy yourself. If you are renting in Czech Republic, the car should already come equipped with a year's toll. If in any other country, chances are you have to get one yourself, unlss a previous renter had to get one and it's still valid.

No toll roads in Germany. You will need to buy your own vignettes as rental cars do not have them.

Thank you. Curious as to why Yahoo labels just about every section as a toll road when there are no toll roads in
Germany.

You should use viamichelin.com for planning.
It shows you not only the correct toll roads, but also the costs, and differentiates between stickers or vignettes and pay-as-you-go tolls.