Can tell timing belts have been done by a silver sticker on either the airbox or the timing cover which has xx,xxx kilometres scratched into it. Belt age is more a factor than raw kilometres when it comes to failure, something like you don't want a belt thats older than 7 years.
To put it in perspective, belt fails, head has to come off, you have to replace 12-24 valves (no idea the cost for genuine vs aftermarket), and theres probably other things you need to take into perspective (valve guides, new head gasket etc), but I don't have much knowledge in that area.
$400 for a 100,000km timing belt kit with: Timing Belt, idler and tensioner pulleys, cam and crank seals, water pump. Cheap insurance. Labour? probably no more than 3-4hrs.