I have yet to do my first DE shave, but my Merkur is on the way.
One of my primary interests in DE shaving, however, is to minimize costs and to simply escape the marketing traps of shaving in the US. I haven't used shaving cream or lather in well over a decade. I've even shaved off a full beard with only hot water and TracII razors and/or disposables, more than once.
So, are there any other necessities for DE shaving besides lather or gel? I am unclear as to the need for a bowl and quality razor blades, and I'm really surprised at the cost of brushes!