Client setup and billing
You can read this article written by ScottyD which helps you to know the best strategy for setting up an account.
To know about Billing option kindly visit this link: http://www.wordstream.com/blog/ws/2012/07/02/google-adwords-billing
Best Of Luck!
In addition to what Anchal said, I would like to mention that Adwords account structure is the vital part of account optimization, which is most of the times skipped. The account structure should be created with deep care and understanding which depends upon what your client is into and how would you like to focus on main areas in terms of services/products.
Look at this reference for good example, which will help you understand more.
For Billing options available in your country, you can refer to this informative article. Make sure that you select the appropriate country so that Adwords can show you what all billing options are available specific to country level.
Hope this helps!