If you are relatively inexperienced and on a budget my advice is to start making things with what you already have. Buy only what you NEED when you need it. Improvise and/or make for yourself as much as you can. You will learn far more by doing for self than if you just buy the latest gee whizz gadget.
Need to find an edge? A strip of cigarette paper will get you within .001. Need to tram a head? A short piece of .250 rod bent at a 90 deg angle and almost any indicator works just fine. R-8 collet running out a bit? So what? Need a fly cutter? You said you have a lathe and a milling machine.
Make chips, make tools, have fun and learn............................Bob