If you can plan your holidays a bit in advance you may consider current promotional deal of Indian flag airline Jet Airways (and their partners). If you want to fly cheap to Bangkok at the beginning of main tourist season 2014/2015 you may consider this solution. They are now offering an open-jaw flights to Bangkok for quite interesting fare starting at €386 ($535).
Considering that Thailand is one of the most demanding destinations during winter season here in Europe this is an interesting solution to visit the country for reasonable fare. The cheapest flights to Bangkok are available when departing from Amsterdam or Milan and you have to return either to London or Germany (Frankfurt, Munich). When returning back to London we have managed to find flights at this low rate only through Orbitz. (booking in $).
Currently many travel options are available between September and December 2014 (your outbound flight to Bangkok has to be however on 30th of November the latest). Flights are routed via London aiport however please bear in mind that you can not skip first leg between Amsterdam/Milan to London otherwise your air ticket would be voided. Thanks to many low-cost airlines flying between all these cities you can get book your connection flight for really cheap fare, the quickest check is through Skyscanner.
Booking sample Amsterdam – Bangkok – London for $535 (€385)
In case of booking of your return flight back to Germany via Ebookers you have to narrow your search to preferred airlines. Please select Jet Airways, British Airways and lufthansa for the best result possible.
Booking sample of an open jaw flight from Europe to Thailand for €386 ($535) below. In this case you would be flying from Amsterdam to Bangkok on 29th of November and returning back on 18th of December 2014.
Booking sample of cheap flight to Bangkok with return back to Germany for €450. In this case you would be flying from Amsterdam to Bangkok on 18th of October and returning from Asia back to Frankfurt on 19th of November 2014.