The name "Kramer" is originally comes from the german word 'kramer', which means a merchant in a little shop, e.g. a grocer. In the Middle Age in Europe lot of these shopkeepers were jewishs, who didn't have legally surname, but when they got the right for the assimilation, they had get surnames, like "Rotschield"-s, who got it from the parasol of their shop, which was red. So the most merchants in Germany's little places got the right to use surnames and most of them took up the name "Kramer".
Imre Kramer, Hungary