That depends on how much money you're willing to pay.
Its usually between 500- 4000 dollars
It depends on brand and tonnage.
Installing air conditioning can be expensive, but the price will depend on a few different factors. The size of your premises, the number of units you need, the type of air conditioning system that will need to be installed, and your chosen supplier will all affect the total price.
You can buy cheap, portable units for a few hundred pounds, but these are often not as efficient and can't make a significant amount of difference to the room temperature. It's best to seek out a reliable air conditioning supplier and ask them directly for a quote. I paid around £1500 for air conditioning in Cornwall, but this figure is likely to be very different from your own quote as the size of your premises may be very different than mine.