Does anyone know of a cheap flight/ airline that i can use to get to Greece (pref; Thessaloniki/ Athens)
I'll be flying from either London or Amsterdam or Rome.... (basically whichever is the cheapest for me to fly into fm China) Thanks

WHEN? Fior how long? single or return? never ever bought airtickets before?
as GR is mainly a seasonal destination-and the summertime about over-for winetrtime there are very, very few direct flights-most of them will in fact go to some islands that are still sunny, like Kriti or Rhodes.
of course-you dont even need to ask that, the national airlines: KLM and OLYMPIC fly between the capitals. neither are cheap.
the low-ciost- aka as no-frills airlines can be looked in sites like flybudget, whichbudget, airninja and a few 10 others. They list ROUTES-youll then have to scan if they actually go in winter-if that applies.
as NL has introduced a extra airtax since 1/7-many flights are withdrawn in slow season,. it may indeed pay off to fly there from nearby Germany-Dusseldorf or Köln/Bonn=CGN, can get ther for €19 by ICEtrain. again: the low-cost sites show when/where