Not at all. Facebook has offered such an easy User Interface that any one can start FB advertising. Its almost like doing online shopping. However I would suggest to go with agency/experts if you are planning some huge spends.
Well, the larger companies hire peoples for proper social media marketing but a small firm can work without proper social media marketing team. All you have to do is to keep your page alive and share it on the relevant groups.
Facebook is an open social networking platform where anyone can advertise his products or service. only the things you need to advertise are
1) A business page
2) A suitable amount in your account