I'd like to get some suggestions and ideas on cheap round trip airfare from Athens, Greece, to Bankok, Thailand, as well as sightseeing in Thailand. I plan to stay for a week or a little longer. Thanks.
Your best chance for a cheap flight would be if you check with some of the discount travel agencies in the Syntagma/Plaka areas of Athens to see what they have to offer. Thai Airways offers a non-stop flight but it's not particularly cheap. I went to their website, plugged in an April date to see what they had and it came back at €817 RT.
Hard to answer without knowing what are your interests are - historical sites, beaches, massage parlors etc.