What was your most successful marketing approach?

So I'm launching my outsourcing IT support and service company in about 5 months and there's no doubt that I'll be bootstrapping at the start, which is why I was wondering what kind of marketing has worked for you guys before? I'm considering putting most of my marketing funds into an event that would get a lot of SMB owners into a place together so that we could explain what we do and how can help etc. It would be marketed as an event that shows you how our company can save you X amount versus hiring your own people. I think this way we could get to the most people the cheapest. Otherwise I may hire a telephone and social media marketer that works on commission, and we could pay upwards of $700 per client that our sales person acquires for us, I'm not sure if that's good or bad.