You can easily pay $30 for custom cut matte board, even for a small piece of art work.  I often print my artwork images with fake matte boards layered into the art files!  Once the picture is mounted in an actual frame under a sheet of acrylic glazing, it's not easy to catch that the matte board is... well... an illusion.  Notice below, the bevel on the board appears convincing enough ...and it is for many situations (not every situation). This "cheat" can save money.  And it's easy.  Just create your faux matte in Photoshop or your favorite paint program.   My suggestion would be to keep it really simple.  However, you will soon realize that creating a matte in this way gives you an opportunity to style and decorate the matte and make a unique presentation.  Note that my faux matte boards are very plain and simple, allowing the art work to take command of the show.  

Here, the slides show some quick experimentation with matching color matte boards with tinted images. 

Green is terribly complex.  It has issues.  For a long time I did not believe green really existed.  I was confused.  But so was green.  And still is as far as I am concerned.  Still, I lapse into moods where I think a space can have sort of a greenish cast but a deep, true green... no.  But I have found green.  With help from my friend red, I have finally discovered green.  Well, actually I think the feeling of green is just a strange way of saying blue.  Okay, so I have not completely seen the light.