Ferrals - yes, it costs a bomb if you park in the one in the same building, and we found it hard to find a parking spot. Sorry - no discount
Twice we also used one across the road from the building entrance, which might have been cheaper, but it is not very large and may fill up. They park your car for you. I think it is just open weekdays.
Other than that, there is cheaper parking at Darling Harbour, but certainly very far to go if you are doing EPU.
For weekends there is a well-priced one a few blocks south on Kent street - I think $10 a day. Handy to know because the one in the IVF building is closed on weekends. Sorry that I can't be of more help!
Good luck
