Is there any other fees whne i arrive in bangkok airport?

i am set to go to bangkok end of this month. I already booked for my two-way flight, when i get there, i'll be staying with a friend. i will be travelling on a budget. i only have minimum cash with me. is there any other fees that i need to pay when i arrive bangkok airport? customs or environmental donation, etc? how much is a regular taxi within city limits? any other tips? thank you!