jp/crupi/revcore/hutch all cages interchangeble, jp not as common as crupi but priced about the same, early jp n crupi peds were made by revcore, hence the similar design, revcore n hutch peds fetch the big bucks, hutch not available in squares n as far as im aware revcore not available in rounds, crupi squares are fantastic for riding, they feel much bigger than the rounds. used but usable crupi/jp squares start at about £40 i reckon and upwards and over a ton for titanium shafted ones, beware as they also did alloy shafts that may not fair well under old school guttage
replacement cages are $29 from crupi and come up a lot on us ebay for peanuts. another cheaper option is to get some nos oddy triple traps as crupi/jp square cages fit straight on, lotta ped for ya pennies and mid school perfect