Magistrate Ahmad Solihin Abdul Wahid meted out the fine to Thangamani, 44, who pleaded guilty to the charge of offering sex service to Lance Corporal Mohd Nasir Abdul Latif.
Thangamani, who is a cleaner, was also fined RM1,000 in default three month's jail for abusing the social visit pass by working as a prostitute.
She committed both offences in front of the KK Super Mart at Jalan Tun Tan Cheng Lock, Dang Wangi, here at 5.50pm on Sept 3.
In mitigation, the accused, who was represented by counsel Harizan Yaakob, pleaded for leniency saying she had to support five children.
Deputy public prosecutor Noorelynna Hanim Abd Halim led the prosecution.