u/Commercial-Shop-408

I’ve got my armies painted, I have a decent battlemat. I need some obstacles and the like to make it come alive. Honestly not too keen on spending an arm and a leg on etsy printed terrain and making stuff from scratch sounds a lot more fun. So my question to you: What are the 5-7 materials to get to start terrain building (recommendations on where to get them welcome) and what are a couple of basic starter projects I could get into? Something to fill a saturday afternoon would be lovely. I have paint, cardboard stanley knives and various glues already if that helps.