1. 4layer pcb from oshpark.com, get three for $10/sqin
2. Paste stencil from ohararp.com
3. Buy Chipquik (actually amtech) leadfree solder paste
4. Build reflow oven (you do need temp monitoring and control, not just any toaster oven)
5. Apply paste with vanilla straight razor
6. Place parts with a steady hand and curved SMD tweezers or ebay pick/place vacuum pen
7. Reflow
For protos placing the parts by hand is fine. For production $2k is reasonable for setup costs. You will need to buy hundred+ at a time to make that approach worth it.
I suppose you could mess about with the various pick and place tables out there, but I wouldn't bother. You will need to build protos anyway.
There is not really anything you couldn't do with hand placement and reflow. I hand assembled the board below. Process was just what I wrote up above.
For 0402s and the bgas even though I could place them with just curved tweezers it would've been super nice to use a vacuum pen. You only get 1 shot to do it right or you have to clean off the paste and redo everything again.
However you can get great results. Read up on BGA process appnotes and the like. There is so much info out there, you just have to spend 5mins looking. If you want a rigid step by step checklist you may be better off with a book approach.