I would stay far away from a set price for anything. Each case is individual.
This time of year is hazard removals before the winds start up.
You can call your past customers, letting them know that you are able to handle new customers, and you just wanted to put a bug in their ear in case their friends, family, co-workers need something. You could give an incentive, such as 5% of the referred party's work as a discount off of your customer's next work at their own house, or you could apply the 5% discount to your customer's referral, instead, at their discretion, though you won't get the extra job from your original customer.
Business cards should be given out like water.
I really suggest trying to cultivate the local business. If I'm at the local gas station on our peninsula, and someone is eye-ing the grinder or chipper while I'm fueling up, I'll sometimes just introduce myself as a local cert. arborist, here's my card in case you need anything, thanks, and have a good day. If the are at this gas station, then they are more than likely living on the peninsula. If they have a fancy car, I'm more likely to go out of my way, figuring they are more likely to have some extra disposable income.