Applicants are strongly advised not to deal with any agents.
The Embassy only cooperates with VFS Global. The Embassy has nothing to do with sellers outside the premises of the Embassy or the VFS Global office, or other agencies or persons approaching applicants in order to offer services. No agencies can influence the processing period or the decision. If any visa agents say that they can influence your application we urge you to immediately inform the Embassy.
Please be informed that many agents also charge unreasonably high fees for services which are unnecessary. The use of a visa agent may also compromise the overall credibility of an application as certain agents fabricate information and documentation.
Also note that even if an agent has filled in the form, you are personally responsible for all information and documents that you hand in with your application.
The same warning is valid for work and residence permits. www.migrationsverket.se/English/Private-individuals/Working-in-Sweden/Employed/How-to-apply.html
No extra fee is required, except for application fee. Link to fees