Which marketing companies have you found success with

Hello Brooke
I am currently putting everything together to start my own company I love everything you teach and I value your experience and knowledge. I want to hire a marketing company to guide me through the process as well as assist me in the marketing for online coaching. Which company or companies have you had success with as there are many out there with lots of promises and dreams. I don’t want to reinvent the wheel if you have some suggestions