Patenting Costs article: How much does it cost to get a patent? $5-8k total (US Patent issued), depending on what kind (design or utility), how complex, and in which countries patent protection is sought.
Patent Prosecution Services are usually one of these three activities:  representing a patent application through examination (responding to office actions),  appealing an examination decision, or  conducting opposition, reissue, or reexamination proceedings.
Patent Agent Legal Services? When it comes to legal rights, in pertinent part, property rights, there are licensed professionals who offer help in exercising or protecting your rights. Lawyers. For patents there are patent practitioners (agent or attorney) to deal with these special rights.