I have one dataframe DATA_SET, which is composed of three columnsc(TEST1, TEST2, TEST3) and a second dataframe DATA_SET1 which is composed of two columns c(key, value). 
DATA_SET<-data.frame(
                     TEST1=c(200,220,200,260,300,290,320,320,360,400),
                     TEST2=c(200,220,200,260,400,290,220,370,260,200),
                     TEST3=c(200,220,200,260,500,290,120,240,160,400)
                     )            
DATA_SET1<-data.frame(         
                      key=c(rep("TEST1",10),rep("TEST2",10),rep("TEST3",10)),
                      value=c(700,700,700,700,700,700,700,700,700,700)
                      )
So my intention is to change DATA_SET1 with melt() function or something similar and after that combine that  with first table (i.e. DATA_SET) to get a table like the one below.

 
     
    