Dude although I haven't searched these forums for the cheapest priced etek I could find, I haven't seen any go for £150, and where I appreciate you've offered £170 for the plain white etek with several scratches, the one we're selling is a more unusual colour, in better condition and unless I'm mistaken, which I very much doubt, has been maintained to a much higher standard!
If you're looking for a great marker that shoots flawlessly and stands out from the crowd, look to be offering £220+
Thanks