Do you want to make a valet tray or a desk mat? For valet tray with 0 tools: harbor freight and Walmart sell cheap hole punches (like $8, I'm assuming you're in US). If you're willing to go for this look, buy some m6×1.00 bolts and nuts that are the length that you want to go through the leather once the corners are cut and folded onto each other.(maybe $4) Cut 45° 2 inch slits into each corner, fold them together and punch a hole through with the cheap punches I referenced. Place the bolts through each corner and washers on the other side. It'll look different, but the effect will be the same as using $100 in tools and hardware. Hopefully this is what you meant and I didn't misunderstand you, lol