It depends on the person who's making the purchase. I've dealt with VPs of programs in the past that had no problem putting $10k per month onto their corporate card without much additional oversight, but I've also dealt with program managers and directors who topped out at 1/10th that.

It also depends on the company. Are you talking about Dell, Toyota or Lockheed, or are you talking about a regional business?

Usually I've encountered needing to go through an arduous traditional procurement process when any one lump of money that's being negotiated over or leaving the building is North of $100k