I started with DIY because I couldn't afford $50+ for a basic hammock, but I could afford $25 for the material to make one. Since then I've made my own tarp and quilts and a few other odds and ends. DIY may not be cheaper al teh time, but I can buy materials as the funds are available and stockpile until I have everything I need for a project. I've never been great at saving and budgeting cash. and having myself a $150 biweekly allowance for food/gas/incidentals means I don't have much left over for gear purchases. And it would take me several years to save up enough to buy a premade down quilt from one of our cottage vendors. But by finding a great deal on a down pillow and purchasing ripstop on sale I was able to put my quilts together in only a few months.
DIY can be cheaper, but you have to be a bit creative at times sourcing material.