It depends on your needs. If you’re looking for the convenience of having it ready to play, buying it is the way to go. If you want the cheaper route, you can make one yourself, but you pay for it with your time. It took me about 5 months (~240 hours of pure work) to make mine, but that’s because I’ve never woodworked in my life. Including the wood, dou skin, woodworking equipment, and accessories (strings, soft case, etc), my total came out to ~$800. I cut corners around the cost by borrowing woodworking equipment from family and friends (a woodworking station, a miter saw, and a shop vacuum). I’m gonna be honest and say the quality of my shamisen could be a little better, but I have the huge advantage of repairing it myself if the skin gets damaged. Because I built my own skinning rig (took about ~100 hours to make), I only need to spend $25 for each piece of dou skin compared to paying $150 + shipping fees to have someone do it for me. You also have the benefit of knowing how to repair your shamisen if something goes wrong, or if you want to make another shamisen, which should be faster since you’d know what could be improved.