Before college, I worked for a big-rig parts, repair, and sales company. I've found that most automotive and industrial equipment places all have accounts with discounts for each other. Depending on the company, employees can usually take advantage of the discount as long as they pay cash and the tax. Be sure to mention it is a personal sale and is a cash-tax sale.
I was able to use the discounts for misc parts at Napa, brake re-lining, machine work like turning drums, disks, and flywheels, fasteners from a place similar to Fastenal, etc. So whenever you walk into a store it doesn't hurt to ask if your employer (or a company you are close to) has an account. Usually it's good for 3% off, sometimes a lot more.
Only drawback is that you have to show up in person and is not the case for all. Some will require a purchase order no matter the type of sale.
I suppose I could have gotten a discount at Cat too, but I couldn't justify putting a 3406b in my 64 ford f100.
