And, let me tell you, those chairs are worth it. I paid about $1200 for my Leap (I needed an extra tank one for a drafting table desk) and have had it 15 years now. 8-10 hours a day my job is to ensure that my chair does not float away using only my 200lb body mass. Not only is it still in good shape* I never have a sore back even after a long day of ballasting. Prior to owning the Leap I’d go through a $100 office store chair in a couple of years.
*the seat cushion was a little worn at the edges and the cushion not quite as supple so I replaced that this year.
Probably a poor selection, or some who drives a “performance” vehicle for pleasure, or possibly an older vehicle The only real thing to concern yourself with is that there has has not been sitting for a long time (weeks/months), but any popular station will have multiple deliveries a week. Get the cheap stuff. If you feel guilty you can run a cleaner and dryer through the system occasionally, but modern consumer vehicles are pretty well designed to function efficiently on a range of gasoline-based fuels.