I did some research on major orthor-k providers in Singapore. Here is their service and price comparison. Hope can benefit other parents as well.

The Point Optical group
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Price range: $1500-2200 for two years
The full package include:
– every 2 month eye checkup
– lense cleaning service
– 1 pair of spectacle for backup
– Free change of the lenses if eyes grow within 2 years

Replacement of the lenses: $800-1100 per pairs

I negotiate with the boss for 1 month trial for $200. If not suitable to wear, can change to other product.
As my child’s myopia is consider low, I am not sure about other degree. You can mentioned my case to see if can get the same rate for the trial.

St Issac
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– Price range is $1800-$2400 for 1st year
– consultation fee: 1st time $55 for a year
– Subsequent year at $45 yearly registration.
– replacement lens at $650/pair
– do not provide cleaning of lens
– No trial period

Optic point@Shaw center
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– price range: $1950 for 1st year
– subsequent follow-up $250 every year
– replacement lens: just increased to $900/pair
– provide free lens cleaning
– 1 month trial: $350

MeeMee Optic
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– price range $1600-$1800, including 2 pairs of FOC myopia lens (no frame). Check up every 3 month.
– replacement lens at $800/pair
– do not provide cleaning of lens