Big money from Toyota, and not sure but they might not extra for the magnetic clutch - which makes it sound fancy but it's not. Guessing but over 500 quid new. Second hand is cheap because you're taking a punt that it's a good unit. If it's not then your system will swarf with bits of A/C pump piston and then worse, the next compressor you try will chew up also, so your system must be flushed and the swarf filter replaced (if Toyota's have one, VW's do - it's just a pipe).
When you buy one, look for one where the wheel freely moves, and with no/little corrosion. Do not buy from ebay - buy from someone on Forum maybe a trader here, and ask them to swap it if it's a dodgy one. Remember that your system needs checking for swarf BEFORE you fit the 2nd-hand unit.