The majority of legal matters take some time to resolve. How long depends not just on the course of action my clients and I decide on, but also the actions of the other party. This creates a bit of uncertainty as to the duration of the case.
In these matters, Retainer Agreements cover some of my fees up front. I try to keep the retainer as low as possible given the type of case at hand. In some simple matters a retainer could be as low as $100. I keep track of the time spent on the matter and bill on a monthly basis.
Hourly rates depend upon the complexity of the case, the amount of work involved and whether or not court time is to be expected.