Projects, like snowflakes, are never the same therefore most jobs are priced in the same unique fashion.
Most often I like to work with the client on a per project basis to determine the cost of a given project as a whole or per article, word etc. Deposits, or initial payments would vary based upon type of work and duration of project. I'm not aspiring to retire from one client so reaching a mutual pricing comfort point is almost never an issue.
I accept payment via check, envelope filled with small unmarked bills or PayPal.