Mia,
Coupon sites are definitely on the rise for obvious reasons, but for many smaller businesses it is hard to offer coupons or discounts when your margins are becoming increasingly thin.
One thing that I have noticed lately, and this pertains mostly to B2B relations, but I have encountered a lot more bartering of services instead of the exchange of funds to get things done.
For example, if I need business logos designed or some development work, I may find a designer or developer who is more interested in exchanging their service for some help in the areas of SEO and PPC, which are specialties of mine. This type of transaction is mutually beneficial because while no money exchanges hands, we both have our needs fulfilled.
As for customers, i always think it is a good idea to provide incentives for participation or bulk orders. This is similar to a barter in my mind. For example, if one of your loyal customers writes a quality review about your business online, in exchange you can provide them with a discount on their next purchase. You both benefit from the exchange.