It was worth about $25 in 2002 when Germany switched to the euro.
If you're travelling to Germany or know someone who is, the German central bank (Deutsche Bundesbank) will exchange old DM notes and coins without surcharges at any of its regional branches in Germany; these are located in most major and many secondary cities.
In the US it may be possible to exchange it at a major American branch of a German bank (e.g. Deutsche Bank, Dresdener Bank, etc.) or at a currency trader such as Amex, but the conversion charges for an obsolete bill will almost certainly eat up most or all of its exchange value.
In 1948 all previous forms of the Deutsche Mark including the Zwanzig Deutsche mark merged into one common conversion rate. In 2002 the Deutsche Mark was considered null and void of value and was replaced by the euro.
The German 1 Mark coins from that era were actually made of copper-nickel, and the highest collector's value would be around $4, if it's still in uncirculated condition.
at todays value a US dollar is less the 2 marks on the market
Deutsche Mark was created in 1948.
Deutsche Mark preceeded the Euro as the currency in West Germany
Duetsch Marks I believe are still valuable. I think they would hold value just because of the fact they are from 1928.
In perfect, uncirculated condition, the 1980 5 Deutsche Mark note is worth $9. In Very Fine condition, it is worth $6. In any other, non-collectible condition, it is worth face value - $3.71.
Deutsche Mark coins and bills can no longer be used in ordinary commerce, but as of 2016 the Bundesbank maintains its policy of exchanging DM bills and coins for euros without restriction. The exchange rate is the same as that established when the euro entered circulation, approximately 1 DM to €0.51
Before the Euro was introduced to Germany, their currency was the Deutsche Mark. There were 100 Pfennings in a Deutsche Mark.
If your question relates to the numismatic value of a 1978 Deutsche Mark coin, it is worth less than a dollar in circulated condition, and US$1 to US$2 in uncirculated or proof condition. This is the case regardless of which mintmark (D,F,G or J) you are referring to. If your question relates to the Dollar-Deutsche Mark exchange rate in 1978, US$1.00 = DM2.00 (FYI, it was US$1.00 = DM2.32 in 1977 and US$1.00 = DM1.83 in 1979).
It was the German Mark, also known as the Deutsche Mark.
Since adopting the Euro in 2001, Deutsche Mark notes are no longer legal tender. They have a replacement value (in a German bank) of approx $7.50. A 1989-1999 uncirculated 10DM note is worth between $10-$20, depending on signature.