Hi mimi, I just came back from KL and BKK. I went to BKK by Jetstar, the return fare was about $200+ inclusive of tax. No meals but the service was very good, no complaints. Tiger airways is also good but you have to board from the Budget Terminal. I went to KL by coach for about $90+ (2-way trip). The coach was very comfy and included 1 meal, dessert & drinks, as well as movies. Very satisfied with the service overall.
Hi noscon, to get to Senai airport, you can take a cab from JB. But I wouldn't advise you to take from outside the customs. If you can, bring less luggage and go to City Square Mall (just past the Mobil station after the customs) to get a cab. Then ask if the cabby will go by the meter before you hop on. It would be useful if you know some Malay. And always travel in the day as it is safer.