The easiest way to get the top values may be to sort the data by Sales and take the first N rows.
DF <- data.frame(Prod = 1:10,
Sales = c(50, 40, 90, 100, 120, 110, 110, 120, 150, 150))
DF
#> Prod Sales
#> 1 1 50
#> 2 2 40
#> 3 3 90
#> 4 4 100
#> 5 5 120
#> 6 6 110
#> 7 7 110
#> 8 8 120
#> 9 9 150
#> 10 10 150
library(dplyr, warn.conflicts = FALSE)
DF <- arrange(DF, desc(Sales)) #Sort by Sales in descending order
# get a subset of the top 3 Sales
Top3Prod <- DF[1:3,]
Top3Prod
#> Prod Sales
#> 1 9 150
#> 2 10 150
#> 3 5 120
Created on 2020-08-05 by the reprex package (v0.2.1)