In this chapter we learned the basics of the Magento payment method implementation. Based on that we built our own simple payment method. Same as with the shipping extension, our extension was built with a presumption of using the default Magento installation with only USD ($) currency and no tax configuration.
When building an extension for distributing, you will need to dig a bit deeper into it, covering the currency and tax calculations.
In the next chapter we will learn how to package and distribute your extensions.