You will need two permits for the Annapurna Circuit Trek, a TIMS permit, and an ANCAP. For most nationalities, the TIMS permit costs approximately 10$USD while the ANCAP costs approximately 30$USD. You can obtain both from the Nepal Tourism Board Office in Kathmandu. You will need to bring passport photos to the Tourism Board Office to obtain your permits. Be sure to plan ahead, as the Office is closed on various holidays and also often entails long lines and waiting times.