I think by 1987 prices were beginning to rise, wouldn't be long before "offers" was to be introduced. I have some lists in the garage from then, will dig them out and see if anything interesting on them.
but even up to the late 80's you could get rarities for a couple of 100. I paid £150 for Sir Ceasar (my first three figure record), half a dozen or so known copies at that time. £150 for Jesse Davis on Era. Most of the stiff that goes for £400/£500, even records that are now £1000+ today were as little as £10/£15.