Paul, I'm surprised no one responded to you ... so I will :-)
When I got mine from Headblade.com I also got their pump.
One pump yields an amount about the size of a large pea or a small bean.
I'm still on the original bottle but it's getting low.
I've shaved daily, never missed a day or doubled up in a day ... and am at 142 shaves from this bottle.
It doesn't take much and a few drops of water adds to the lather initially or revives it midway through if necessary.
Your mileage, of course, may vary. (YMMV).