When I worked for an electrician (many years ago), I would have to go to Grainger to get stuff and would charge it to the business account.
Eventually I left that company and began working on my own, doing all types of home repair, and construction, I did not open an account with them, since most of my work was carpentry. But I did some electrical and plumbing, as well as other stuff like painting, floor tile, and some appliance and furnace repairs as well. Every so often I would need something from Grainger, (particularly motors for furnace blowers). They sold stuff to me with no problems. They did put me in their list, but I paid cash when I went there, so I never bothered with getting an account.
Companies that demand they will only sell to businesses are losing money. A sale is a sale.
I still recall when I was still in high school, I played with electronics all the time, and that was my hobby. I bought all my parts from a local electronics store. One day I went there and the name on the building had changed. I went to the counter, and the guy asked me what company I worked for. I told him I was just a hobbiest. He said he could not sell to me unless I worked for a company.
Fortunately another guy saw me, who had worked there for years, and knew I had been a regular customer. He came over by me, said that their company had been sold and was under a new name, and they only sold to companies now. He grabbed a sheet of paper, and said "what do you call your company? *Make something up*". I just gave him my first name with "radio and tv repair" after it. He wrote down my address and phone# and said "from now on, when you buy something, just tell them it's for (business name we made up).
After that I had no problem buying anything there....
There are always ways around these things. The guys at the counter dont care who shops there, it's just soem guy sitting in an office which has some important title on his door, which makes up these nonsense rules.