Create a simple number vector

df = c(123454, 39384894, 123)

Use Pretty number to have the output breakout with commas

prettyNum(df,big.mark=",",scientific=FALSE)

## [1] "123,454"    "39,384,894" "123"

Same output using format

format(df,big.mark=",",scientific=FALSE, trim = TRUE)

## [1] "123,454"    "39,384,894" "123"

Same output using scales package

library(scales)
comma(df)

## [1] "123,454"    "39,384,894" "123"

add usd sign to output

sprintf("$ %3.2f", df)

## [1] "$ 123454.00"   "$ 39384894.00" "$ 123.00"

Change number to a percentage

x <- c(0.65, 0.05, 0.99)
sprintf("%.1f %%", 100*x)

## [1] "65.0 %" "5.0 %"  "99.0 %"