Defys second hand, 300-350. Also be very careful of the condition. Number of times we get people come into work who have been given bikes and we have to condem them or give them a massive repair bill to actually get the thing ridable .
You just need to work out wether you want to go double or triple (or single if your crazy) and then decide what ratio you want at the back. Shimano brakes come with crazy long hoses though so you will probably want to get them fitted in a bike shot as they will have a hose cutter and barb driver.
yeah i got a semi local place in mind for installing it
but it comes with XT Front Derailleur FD-M786 Unisize which i do not think will work simply because of the bracket & the curve in the bike frame where it would be sitting