In my Florida area, I get it from the local wholesale supplier; like others have mentioned, he'd deliver it if I could take 300 gallons or more, so I pick it up. I had to fill out a form that the distributor keeps on file. All I save is the road tax; I'm not certified as agriculture, so I do have to pay the sales tax. I still save about 40 cents per gallon.
The fuel is the same whether off road or on road; they just add die to indicate that the road tax hasn't been paid. I bought a new 55 gallon steel drum from the distributor for $20; they would have given me an old one free. I drive up to their pump with the barrel strapped upright in the back of my pickup, they fill it, and I drive the 6 miles back to my property, and use the FEL to unload it. I'm not sure what the D.O.T limit is for fuel transportation in Florida, but no one has ever bothered me. I'm pretty sure I'm legal as long as it's in an open truck rather than a closed vehicle. I suppose there is some point at which I would have to placard the truck, but at around 50 gallons I'm sure I'm safe, because the diamond plate tanks in pickup truck beds are around 50 gallons, and they don't have to placard.
That reminds me -- I'm empty, again, and have to go get some early next week...I use my tractor a lot, get between .5 and .7 gph, so I use about 5 gallons in an average day (8 - 10 hours). I tend to go through a drum every month to 2 months.