You can read about the shortage causing prices to soar by googling this search phrase - "R22 refrigerant cost".
Because Freon production is being phased out by 2020 (by EPA regulation) and manufacturers are stopping making it right now to reduce potential EPA lawsuit liability for producing "hazardous" greenhouse gases, prices have gone way up. However, there is still a substantial markup - wholesale price is around $20/pound in quantity (30-100 pound cylinders), and a normal system takes 4-10 pounds (usually about 5-7), so the incentive to highly mark it up is high. The law also requires that it be recovered and either reinserted or recycled for reuse when a system is serviced, not vented, so that adds substantially to the cost of recharging.
After 2020 its manufacture will be totally illegal, so its cost will become totally exhorbitant, and it will continue to be used only in existing systems that need topping off or large commercial building systems. Home systems that totally lose their charge will end up being cheaper to replace than to recharge. Replacement gases like EF-22a, R-290 and R-410a are more expensive to make and handle than Freon (R7 and R22) and are less efficient, and are supposed to be used in all new systems, but they also are being considered by the EPA for future banning.
Some existing systems can be converted to R-410a or similar refrigerants by flushing and changing lubricants, but generally a converted system will be less efficient and not have the same cooling capacity with the replacement gases.
Because of this, many commercial building air conditioning systems are being designed for chilled water rather than direct refirgerant gas systems, and commercial freezer systems are going back to the old standby ammonia, but ammonia leaks are very dangerous and it is unsuitable for home use, so in the long run it is likely that more and more residential systems will, over the next decade or so, start being geothermal heat pumps rather than pressurized evaporator air conditioning systems.