My slotted angle steel order from McMaster-Carr arrived yesterday!
Overall, I am pleased with McMaster-Carr. I ordered the steel on Tuesday and it arrived on Thursday! The cost has gone up slightly from when this thread was originally created. Also, there is one annoying issue with McMaster-Carr that should be mentioned. The shipping cost was a complete mystery until after I placed and received my order. Below is the receipt I received by email this morning. Fortunately, the shipping cost turned out to be the $25 that someone else on this thread said it was for him.
2 each 8968K26 1-1/2" X 1-1/2", 6’ length__17.32
6 each 4664T65 2-1/4" X 1-1/2", 6’ length__78.06
16 each 4664T22 Steel Corner Plate, 6"x 6"_38.56
2 packs 4664T61 Bolts W/nuts & Washers__14.84
I already have casters, so I didn't need to order them. I'll start cutting it up tonight using the cheap angle grinder I picked up at Harbor Freight. Hopefully that will work for me. I'll post pics of the process later.