R: "$ operator is invalid for atomic vectors"

I would like to make a function returning a particular column of a dataframe since I have several dataframes whose names vary of just one digit. For example, I have:

mtcars1 <- data.frame(name1 = mtcars[5, 1], name2 = c(1, 8, 2, 9, 9))
mtcars2 <- data.frame(name1 = mtcars[5, 1], name2 = c(1, 8, 3, 9, 9))

foo <- function(i){
  x <- paste0("mtcars", i)$name2
  return(x)
}

foo(1) is supposed to return 1 8 2 9 9 and foo2 is supposed to return 1 8 3 9 9

The problem is that I have the error:

Error in paste0("mtcars", i)$name2 : $ operator is invalid for atomic vectors

This is surely a straightforward question but how can I do it?