Here is some nitty gritty airport info for Ngurah Rai in Bali:
Upon landing in Bali, non Asean nationals such as US citizens and most European nations must get a Visa on Arrival. Look for the counter where you can purchase one for US$25. You may pay in equivalent pounds sterling, euros or Singapore dollars (these are the currencies I have had experience with) but you must pay in CASH. I recently saw people in dilemma when they learned that credit cards are not accepted! Helpful information about visas can be seen on Expat Forum
You will then need to get into another line to clear immigration. It pays to be sitting towards the front of the plane and race to the counter to avoid potentially long waits.
After collecting your bag, you will need to put all luggage through an Xray machine on the way to clearing customs. You are permitted only one bottle of wine or liquor per person duty free. Bringing illegal drugs into Bali is a serious offense as the many Europeans living in Kerobekon prison will attest.
When you leave Bali, you will also need to pay an exit tax of IDR 150,000 and this MUST be paid in rupiah. There are conveniently located money changers if you need them, but again, cash is essential.
Ngurah Rai airport is not a bad place to be There are a couple of Periplus Bookshops and some pleasant shops to browse in. There is even a Coffee Bean and Tea Leaf there now! You can pick up last minute wood carvings, Balinese music, snacks and even Jamu. Best of all are the omnipresent foot reflexology shops everywhere. 10,20 or 30 minutes of foot reflexology before your plane trip is just the thing.