Well... I'd start by asking you why you're charging so little? That alone brings about suspicions on two levels. 1.) Your firm offers a low quality service and you're out to make a quick buck... or 2.) The service in general is grossly overpriced if your company can afford to discount it 90% and still be profitable.

Mind you... I'm not saying either of those is the case... but those are the thoughts that popped into my mind. 

You might be better received by only discounting your service by 10%... but use some of the increased revenue to include or giveaway something else of a high perceived value. Maybe their choice of fresh flowers for the office, because your service is like a breath of fresh air. Or a free pizza day might work well too. Be creative and cause a spectacule. Hire a company to come in and do foot massages at their desks, because you believe in treating your clients like royalty. Outrageous and ridiculous right? That's the idea! Your company will get talked about and never forgotten. Hope that helped.