Many of the subway tiles come with built in spacers for a small grout line - though you have to do some math to check that you don't have a gap at the top by the upper cabinets and fudge each tile a bit (a very little bit) to make it come out even. Mine have about 1/16 to 1/8. The grout line looks a little bigger after it is grouted.

Here is mine:

https://www.houzz.com/photos/my-pics-work-in-progress-phvw-vp~57088087