There are so many Refrigerants in use that there is no way to answer this question. Best guess R22 or R134A
Alot
Most new equipment is built for and charged with R410a, a refrigerant with much higher pressures than the R22 used for decades, R22 units are still available, dry charged however, you must fill them with R22 onsite. This is how new R22 compatible equipments being sold still.
Absolutely not ... R410 operates at much higher pressures than R22, and mixing would do nothing but contaminate both refrigerants (and possibly mess up your system)
New, i think it is £105,000 for an R22. Yes about 3,00,000 USD.
Current price depending on location $40-60 per lb.
Wal-Mart do not have r22 freon, this is a false ad.
r22a
No
69.9
No
12 r22