Used to filling multiple containers of 98 for the rally car. Most was 8x 20 litre.
Before BP stopped their smart fuel thing, it was multiple $40 transactions working my way down the line of containers then "fill and redeem" the final 50 litres. Depending on how much I'd accumulated prior to the trip, the savings on that final fill was impressive. Aside from the $500-ish it took to get there.
Have had to let a car pulling in behind know that "I'll be a while" a few times when I'm filling pre-trip. It's less of a problem when I have the trailer on the back as I'm usually taking up both pumps of a bay.