DIY: Gallery Wall Arrangement Ideas - plus many other guides, such as yardage guides for upholstered furniture, window treatment & terminology guides, area rug size guides, etc. This is an excellent resource!!!
How To Create a Gallery Wall on a Budget - I was able to purchase IKEA Ribba frames in a variety of sizes for just under $200. My notes on the diagram above show the breakdown of sizes and associated costs. I bought 14 frames but used 13 for the collage. I decided to mix the wood and black and purchased half of each finish.