I dont want to spend any real money to paint a subway tile in my mobil home kitchen for a backsplash. It is old and money is an issue
$30 Faux Subway Tile Painted Backsplash Tutorial
you can also buy wallpaper that looks like faux subway tile
Then just paint with oil based paint after you clean it very well.
Paint it all white then use two parallel strips of painters tape to make the grout lines. Decide how big you want the grout lines and then use to painters tape. You will be painting the narrow space between the tape with a light grey or brown paint to mimic the grout. Seal it all to make it durable.