I Am 67 Years Old And On Medicare. I Was

I am 67 years old and on Medicare. I was diagnosed with asthma two years ago and prescribed Ardair 500. The cost for one month is over $400 which I can't afford. I started ordering from an online pharmacy NorthWestPharmacy.com. I talked to my lung doctor about it and took the first discus for him to look at. He couldn't see anything that alarmed him and so I have been ordering from them ever since. But now they sent me Seroflo instead of Advair. Do you think it would be safe to take?