Good idea for sellers, bad for buyers. IRL this has resulted in higher prices for customers when all prises are "fair price and up" and thus it's been outlawed in some countrys. And who's to set the price tag?
Do a bit more research before you buy something and ask around if you're unsire and you won't be fooled and if you're lucky the seller hasn't done his homework and you'll get it for peanuts.

A B1230 is anywhere from 30-110€ (or more if looking at inzane ebayers) where I think a fair price is about 50-75€ if it's a MK4... MK1&2 is 20€ less and MK3 is 10€ less.
A B1260 is hard to come by... Ranges from anywhere between 120€-250€ (or more if looking at inzane ebayers) where I think a fair price is about 160-200€.
0-16Mb on the card is nothing extra, 32Mb is +5€, 64Mb is +10€, and 128Mb is +25€.