You could always mark your service as on sale but it didn't do much. Now, it does. When you mark your service on sale it adds a red listing image:
A strikethrough and new red price in the service listing:
A new badge in the service listing:
Buyers can select to view only services on sale in the upper left:
You can see the sale has an expire limit. Offering a "sale" of your service with an expiration date causes a sense of urgency. This sense of urgency will compel buyers to purchase your service immediately instead of waiting, thinking about it.
How to Use
You can only put existing services on sale. You cannot set new services on sale. To use, just edit your service, check the On Sale checkbox, add a price and expire days.
You can only set a service as on sale every 31 days. That is, 31 days from the time your current sale expires (IE: if you set on sale for 10 days, you can't set it on sale again for 31+10 days = 41 days).