Why do you need a merchant account?

A merchant account is necessary for businesses that want to accept payments other than cash. This would include credit and debit card payments. A merchant account can also be setup for other services like ACH.

When should I sign my business up for a merchant account?

A merchant account should be setup after a user is able to set their business up. Ideally you setup a merchant account when you open your business but it depends on the type of business you own.