First of all, I'm not a business owner. Nevertheless as a trained business consultant and someone who has worked in getting new customers using said deals qualifies me to give such advice. This doesn't mean that it will work for every situation, so I offer no guarantees for stellar results. You didn't pay me, so don't expect much from this.
Deal of the day websites, in a nutshell work with companies to offer really low prices on a product or service. Usually, the customer pays a certain dollar amount and the website owners take half of the proceeds; the business owner takes the other half. Ideally, said business owner can upsell the customer or at the very least expose said customer to the product and service to win them over. The customer gets a great deal and the website owner also gets their cut. Should be a win/win/win for everyone, right? Not necessarily.
Problem is that all D.O.T.D. customer are aware of the true cost of the good or service. The cost to get a customer is $300 give or take a few dollars. If you want to participate in one of these "deals" my experience is that you will still spend about $300 to get each new customer depending on the volume. There's probably some statistical formula for this, but statistics were never a strong suit, so you'll have to trust me on this one. I believe this has benefited the firm I work for, but you have to remember that you're likely selling your service for a cut rate. The customer is going to expect cut rate prices for everything. Likely he or she will balk at anything deemed "expensive" or "full price;" and many will even turn down essentials (your furnace has a cracked heat exchanger, or your control board is fried) to retain their "deal."
If this is the type of service you're offering, you're probably going to find an opportunity for the guy who can undersell you, or more likely for the D.I.Y. homeowner who will order the part on the Internet. Again, in my experience, these are not the customers you want. You don't want customers to undercut your business, but those who want you to do it for them. Isn't that what we all want? The best way I've found to get customers who are on the fence is through discounts. After all, you've discounted the basic service. As the saying goes, half a loaf is better than none at all. Ideally a smaller discount should be in order, and limiting the amount of those who can participate will also help if attitudes really go south. Give the customer your best product and service for the money and never forget to make them aware that they're getting a screaming deal. Maranatha.