For divorce under the ground of "Consent" ie.雙方同意離婚, and no kid, it will be quite cheap. Remember the 超人律師嗎?
If you got financial problem, go to Legal Aid 法律援助署 申請. of course they have to consider your case first, and you need to pay a bit of money, not free of charge.... You may dial 1083, the address is in 金鍾.
For easy case, it will take about 6 months to have the parties divorced.