Refrigerant work done the way the manufacturer specifies, which is by weight and after the system has been repaired and evacuated.
900 rufiyaa for a standard split unit on R32, including the vacuum. A cassette or a larger system is priced on its charge weight.
There are two things worth understanding. The first is that a sealed system does not use refrigerant, so a unit that needed gas last year and needs it again has a leak, and every top up is money spent on postponing the same conversation. The second is that R32, which nearly every new unit sold here uses, cannot be sensibly topped up: it has to be recovered and recharged to the weight on the nameplate, because adding to a partly leaked charge changes the balance and the unit cools worse than before.
We pressure test with nitrogen before charging and we vacuum to a gauge rather than for a fixed number of minutes, which is the shortcut that leaves moisture in a system and kills a compressor in three years.
Gas is weighed in front of you and the weight goes on the invoice.