Patent Application Fee
Patent application fee includes an official fee to be paid with Patent Office and a service fee to be paid to legal representative (i.e., patent attorney). If one is going through patent prosecutions from filing to registration without any help of patent attorney, only official fee is needed to be paid. Whereas, if the prosecutions are conducted with the help of a patent attorney, one needs to pay both of the official fee and attorney service fee.
Official Fee
For examples of official fee, electronic filing fee of patent application is 38,000 KRW (Korean Won), and basic filing fee of a request for substantive examination is 130,000 KRW to which additional fee is added according to the number of claims. And lump sum of registration fee and annuity fees for 1st to 3rd years is 45, 000KRW (basic fee) together with additional fee calculated according to the number of claims.

Applicant as an individual or a small-sized entity is exempted from 70% of official fees. Further, medium-sized entity is exempted from 50% of official fees, and students or handicapped is exempted from 100%.

More details of official fees can be referred in the following website.
Attorney Service Fee
Attorney service fee is paid for professional works done by patent law firm for patent prosecution. V.A.T is usually added to the attorney service fee. The attorney service fee is categorized as application filing fee, responding fee to Office Actions and contingent fee.
Application Filing Fee
Application filing fee depends on how much time is spent for preparing and filing application documents. In other words, it can be varied according to level of difficulty, whether a direct interview of drafting engineer and inventors is needed, drafting engineer’s experience and career, time spent for drafting and so forth.

Courtesy discount may be offered when many cases are ensured to be entrusted or when many applications are filed in the same technical field.
Fee for Responding to Office Actions
When an examiner found grounds for rejection during examination, Notice of Preliminary Rejection will be dispatched to the Applicant (or the representing patent attorney). The Applicant should respond to the Office Action by preparing and filing Amendment and Argument to overcome the grounds for rejection. Service fee for responding Office Actions is incurred in this stage.
Contingent Fee
Contingent fee is paid when the application is successfully registered. Usually 100% of a basic filing fee is charged as the contingent fee.