To visit Indonesia I recommend doing the Visa on Arrival in the airport.
Below I will explain the process we went through in Denpasar Airport in Bali but it is safe to assume the process is similar at the many other airports in Indonesia.
Depending on your flight, you might be given an arrival form to fill out while you are still on your flight into Bali. If you do not receive this form on your flight, simply pick one up from one of the officers in the airport and fill it out.
Next you go to the payment counter.
The Visa on Arrival costs $35 per person.
Make sure you have cash! They will not accept credit cards and I did not see an ATM in the visa area.
Once you pay, you will receive a receipt of payment which you then show to the immigration officer with your passport and arrivals form.
Then you will wait in the immigration line to get your passport stamped.
Once completed, the officer will return to you a departure form which you will need to leave the country. DO NOT LOOSE IT.
And welcome to Bali and Indonesia!
NOTE on leaving the country:
in addition to the departure card that you receive when you arrive, there is a $20 per person exit tax to leave Bali. There are ATMs in this area of the airport but it is best to have the cash for this ready so you don’t pay ATM fees for a small withdrawal.