What is the easiest way to make a faux brick wall?

You can buy faux brick panels - and apply relatively easily! This is a really good tutorial:

https://www.hometalk.com/diy/decorate/walls/faux-brick-wall-23947902?expand_all_questions=1

Also check peel & stick wallpaper . There are a few that look like brick. Easy to apply and comes off easily without damaging your walls if you want to remove it a couple of years from now.

Wal Mart & Target both sell it.

How about stencils?? Mix and match colors of your choice....

You can purchase brick stencil and paint on the wall. Use varied colors to give the look of old brick to make it look more authentic.

I know it takes a while to complete but stencils are the way to go! Send pictures when you're done, so we can see your faux brick wall! Also I like the stencil idea because even if it's a month or six years down the road, it is simply redone by painting and not removing brick panel board or something of that sort. It's simple and effective and it can look very real based on blending of the paints. Good luck!