Before answering the question, you should really consider one of the two options.
Option 1: You have less time to manage your business but have more money
Option 2: You have more time, but less money.
In case of Option 2, its better to work with freelancers for multiple reasons. Since you have time, you can supervise the work done by freelancers and get the most out of them at a lower cost.
In case of Option 1, its better to hire an agency as they have set processe