You will need 3 things at a basic level before you can download anything:

• A usenet provider, which will provide servers to download content from. Many offer in-bulk deals (yearly) which can average out to as low as 3-4 USD a month. Which providers are recommended?
• An NZB indexer. An .nzb file is akin to a .torrent file in that it contains a map pointing to the location of the content that you want to download. Can be as cheap as 10 USD a year. What are the best indexers?
• A download client (See: Usenet downloading software), into which you will feed your .nzb files in order to begin downloading your desired content. Which client is recommended?