Review the options for transaction handlers (listed below in resources section). Each of these vendors will be able to provide a secure transaction for your fans, but they each have different pricing structures and services, so choose the one that best fits your needs and budget.
Register with the transaction handler of your choice. In some cases, you may want to register for more than one of the choices. For example, you could use E-junkie for your shopping cart, and become an affiliate with ClickBank, and link ClickBank products through your E-junkie account. You might do this if you'd like to recommend the music of a band with songs in ClickBank to your fans, and you'll make a commission on the referral.
Review each vendor's policies, procedures and processes for billing transaction costs, refund policies and support materials. You'll want to be aware of how they handle problems that your fans may run into with purchasing your music, so that you can assist.
Set up a sales page on your band's website. This is where you describe your products, whether it's a single or a collection of songs comprising an album. Enter the price of each song or album. Include details on the file format and the size of the download file.
Upload your digital file to your website (ClickBank) or to your transaction vendor's site (E-junkie). Register your product (file) on your transaction vendor's site. If you are using ClickBank, put the URL of the file you uploaded to your site. Your PayPal account is needed to receive payment for your sales, and often you will be billed through your PayPal account.
Copy the HTML code from your vendor's site to your site's sales page. Usually, this is the link your fans will need to click to purchase the file. When they click the link, they will go to your vendor's site to complete the purchase securely, then they will be directed to a page where they can download their purchase.
Perform a test purchase on your site to see that everything works properly. If you have an error when clicking the link, you will probably need to contact your transaction vendor for assistance.