re: If you want to own an AR-15, you should build it

Make sure you have some masking tape to cover your receiver so you don't scratch it while putting in the bolt catch roll pin. that is by far the hardest part of the whole thing. i put my last one together on the kitchen table. A receiver block and a vise would be helpful for some things though. Also make sure you support the trigger guard ears so you don't break them off while putting in that roll pin. I found that a scrap piece of 1/4 inch plywood worked perfect for that part. I also used a box cutter to hold down the front take down detent while putting in the take down pin. that part is a bit tricky and if you slip the detent and spring will shoot across the room. happened to me the first time and luckily i found both parts.

ETA: Only tools i bought were a punch set and a castle nut wrench for the stock.