Since I did not travel for some years anymore my experience is getting zero. I have to go to Spain before the beginning of October this year due too only some official paperwork (no legalizations not possible, because I have to leave my thumb-print and no, this is not for prison-reasons but this is a very common identification method in this country on ID-cards etc.)

I like to know if I have to book long in advance and where I can make a booking for a reasonable price.

Thanks for sharing your experiences.

The obvious answer would be to enquire/book on-line. Try Thai International: http://www.thaiair.com/