To be honest, and free flights aside, I think it’s the norm for a trip to a CL final to be quite expensive. Unless you get ahead of the game and take a punt on some cheap flights, most fans will end up paying a fair bit to get there.
Like you, I did the Sport Options trip and paid the £599 for 2 nights in a hotel with single room supplement as my mates were dithering. In the end, they booked on but did the flight only option and bagged a cheap apartment so I could’ve saved a few quid there but I couldn’t afford to wait around for them.
Overall, I thought it was a great trip apart from the result. I think the damage for me was in the region of £1150 in the end. I was surprised at how little I spent over there - Porto’s quite an inexpensive city.