If its creaking make sure before you buy it the creak really has gone.
A creak can mean a fracture or something loose or about to fail - in the handle bar area could mean its had a very hard life or not been looked after.
Ive been to that place called "yeah we can get rid of that creak no probs" and its a LIE, Evan cycles suck fixng some things and this was on a 1200.00 squid Trek.
Check for play in the suspension - sit astrude the bike off the saddle, apply the front brake and attampt to roll it back and forwards, any clonking or movement thats not a flex or natural movement then forks may need a service.
Check all the bearings - wheels, headset, bottom bracket and pedels.
Check chain play - put the gears inthe biggest rings and on the front chain wheel see how far the chain pulls away freon the rings by pulling a link away, more than five MM then a new chain should be considered.
Are the wheels true? - turn bike over and spin the wheels looking at a point of fixed contact and see if theres any wobble - buckled can mean hard life maybe a crash.
Do the gears shift well? - again, if not, maybe not really looked after.
How old is the bike? If its a year or two old and inmint then 200 max, older than that and 175-150 max Id say. Its a lowish spec bike with nice forks so some componants are cheaper to keep costs lower e.g the gears/seat/seat post/vbars/stem and so forth.
Oh and whatch for cable stretch on the cable disk brakes, if there sloppy they really do struggle to slow you dont effectivly.
You basically want the bike to feel tight, no rattles, clonks, grinds crunches or thuds
Hope that helps.
Kipp.
