I have been totally stunned at just how expensive EPing is. Nobody ever mentioned that to me when we got started. That's partly because my baby requires these very expensive nipples to eat with. It starts with the hospital grade pump rental fee or purchase -- a Symphony is about $1200-1600 to purchase -- and then all the parts. I spent probably $60 on horns; I bought the PumpinPals and hated them, and so I kept buying different sizes hoping to find the right ones. Then bigger bottles because 5 oz ones are too small. Spare this and that. It all adds up. Faster than I anticipated.
The other shocker was just how big a diaper bag I needed. Having to haul around a pump (Freestyle) and that stuff, along with bottles, in addition to diapers, has been a big change. I went through about 5 diaper bags until I found one big enough that actually works for us; it was custom made by a mama here, actually.
The time factor also kills me. I have had people tell me that I must save time by not having to nurse, but I really don't. I can see how it might save time for someone who is WOTH and then has someone else to help with baby at night though, absolutely. No cluster nursings to deal with. I can see that as a benefit.
Now, to try to put baby down and hope he stays asleep so I can pump. That's the difficult part. Babies aren't meant to be apart from mom when mom is there.