I would suggest a Lee 20# pot, welder's gloves, leather apron, face shield, thermometer, and a hot plate. Add the mold of your choice (Lee makes decent molds for relatively little money, you can go wild with molds later if you like this hobby). That is about all you need to actually cast. After that, you will need a way to lube or powder coat, and then size. I am a lazy, cheap bugger, so I either tumble lube or shake and bake with Smoke's powder coating, then size with Lee push through dies.
If you are doing much 45, you will appreciate a 20 pound pot. With a 6 cavity Lee 452-200-SWC mold that pot empties fast.