Hey! I really think you need some previous background before running your own business. It is good to have experience working with experts in the field to understand the principles of the main pillars of digital marketing. It is not easy to understand the global picture. However, if you need to start intermediately your own agency, low your prices and learn with your first customers. Be honest and say, hey, I will low your prices but I will show you benefits in the coming next 5 months...later on lets bargain again.... If you get more leads, they will pay you more, it is pure ROI. Measure and tell them what are you achieving for them. After this, when you get a clear understanding of your strength and weaknesses then think in subcontracting, but please, do not outsource the core of your business. It must be under your control. And be mindful...if you want to subcontract a service, it is recommended to have previous experience to take advantage of the service offered by you subcontractor. Hope it helps