From another thread on this forum - I don't know how to link to a specific posting, so here's a waste of bandwidth:
Part 107 rules will create a new class of FAA pilot certificate specific to flight under Part 107 rules. This operator certificate would be obtained with a written test. You can expect to pay a Flight Instructor to verify your citizenship ($50 to $100), and a testing center to administer the test ($150-$300). The Flight Instructor or FSDO needs to verify your citizenship because apparently the Test Center personnel are too stupid to look at your passport to verify that you are a US citizen. In reality, CFI's have received Homeland Security training that makes the CFI acceptable to verify your ID. I don't know why the Test Center personnel couldn't also do this training. After all, these are the same testing centers that administer the written tests for other FAA certifications and Homeland Security personnel. All total, your UAS Operator's Certificate will cost between $300 to $500. None of which goes to the Federal Government.
There is no schedule of when to expect Part 107 final rules to be released and adopted. Late next year would be fast. My bet would be on early 2017, but that is still Bureaucratic light-speed for any rulemaking process that normally takes many years. Section 333 exemptions are valid for one year, so most Section 333 holders will have to petition for an extension at least once. Part 107 rules will make Section 333 exemptions obsolete and the FAA would be unlikely to renew them after Part 107 is finalized.