Well, 500ml is about a pint (US liquid measure), and Ben and Jerry's sells 6 pints for $54.95 via mail order. So taking 1/6 of $54.95 gives us about $9.16 per pint delivered here.
Hope that helps. Nearest Ben and Jerry's to here is 100 mile roundtrip so I can't give you the 'walk-in' price.
P.S. I only knew the milliliter conversion because I had to look it up for my
whale cock blog post yesterday.