You can now accept eChecks (ACH) in your storefront through Authorize.NET using Accept.js (beginning in version 10.0.13). Enabling this option is simple, just select the option for "E-Checks through supported gateway" in the Configuration - Site Setup Wizard - Credit Cards & Other Payment Methods section, and ensure that "AcceptJs" is selected and setup in the Payment Processing Solutions section of the Site Setup Wizard.
When enabled, a payment option button will appear on checkout for "eCheck". This will take the customer to a check information collection page similar to the credit card collection process.