Recently diagnosed with ET/mild PV, I too am about to start treatment for the first time. They Mayo 2nd opinion MPN specialist said why not try Interferon, so when my local doc said: HU or interferon, I opted for interferon. I just had my first phlebotomy yesterday, will have another next week to get my 52% Hematocrit level down, then get my first Besremi shot. I was surprised to be offered Besremi rather than Pegasys, as I think my town is rather backwater compared to big cities, but that's what showed up as on offer for me. The clinic financial people will talk with me about expense on Monday. I have traditional Medicare, supplement G and part D for drugs, but it will be thousands of dollars each year if I can stay on it. Her first estimate was $18,880/year, but at that point she did not know about my "gap" plan, so we'll see. They say companies do some $$ sponsoring, for political reasons, I suppose. I was expecting to pay $3300/year or so for Pegasys when I last looked into it. But then no one is asking about the financial pain! (sorry, just on my mind...) I will definitely post after treatment.