In this demonstration, we will use the following image and add backgrounds to it:

Open a new document of 10x10px, create a new layer and either hide or delete the default layer. So we are left with a blank canvas. Then zoom in and use the pencil to draw a 1px line like so:

We can either use a transparent background or a colored background for different effects. Next, press Ctrl+A to select all, then goto Edit > Define Pattern. Give it a name, and then go back to our original document. Choose the Paint Bucket tool and then in the toolbar at the top, select Pattern instead of Foreground:

Then from the drop-down menu next to it, you will see a list of patterns. The one we just created should be at the bottom - select it. Now either select the background layer or create a new one and fill. We will get something like this:

Or if we used transparent background on our pattern, we'd get this:

Using this technique, we can use a multitude of colors and directions of lines. Here are some examples:

In PhotoShop, we can define anything we create as a pattern, which can be a really powerful tool.

We can also use these patterns in Layer Styles. Let's open up the styles of the money layer and goto Pattern Overlay. Here we can overlay a pattern we created, such as the same as the background:

Or we can choose another pattern and play with the Blend Mode and/or opacity settings:

Many many many possibilities exist in the world of PhotoShop, and the more you experiment and play around with settings and values and filters, etc. the more you will find things out.