I use grainger for certain things- Mainly because I am between a 1 and 2 hour drive from decent industrial suppliers, so if I need something like a high bay light, or a motor starter, I can either drive for 3 hours in terrible freeway traffic, or call Grainger and have it here the next day.
There is a small Grainger in my nearest town, 20 minutes away, and they are very nice- in fact, they have a huge industrial glass front icebox in front, full of pop, with a big sign on it, "compliments of Grainger"- and they have a popcorn machine as well.
Its true, they want you to be a business. Well, I have been a business since about 76, and have always found it is well worth the cost- in my unicorporated area of the county, I just need a state licence, which is something like 35 bucks a year. I collect and pay sales tax, and pay B&O tax (state business and occupation) but only if I make money. In exchange, I can buy wholesale from anybody I want, and I save a whole lot more than 35 bucks doing that- my abrasives alone, which I get from Klingspor, save me several hundred a year over retail.
If you are actually in business, I have found that it is a lot easier to follow the rules than not- otherwise, sooner or later, somebody catches you, and it always ends up costing a lot more.