Hello, can I ask where I buy cheap 3months Visa...

We would like to inform you that you can get free visa through brokers offices or families there or immigration offices by paying commission before, that visa grants the holder to work in the country without sponsor.
For the price it is differ according to the duration and validity and may reach 1300$ for 6 months or a year.
So you have to look for offices to grant you the free visa.