This sums it up nicely.
I went last year, the beginning of 3 months backpacking across Europe on a rail pass. Stayed in a hostel in Nice for 25 Euro a night and it was around 7 Euro (return? can't remember) for the train into Monaco each day. The hostel I stayed in was one of the regular Bus-A-Bout stops so it was practically full of Aussies (so is most of Europe actually). Probably the cheapest F1 you can go to if you do general admin and are already in the 'area'. 40 Euro on Saturday for quali and 70 Euro on Sunday for race day. General admin is the hill on the western side of Monaco, on Sat I had an awesome view for quali but admittedly couldn't see shit on Sunday. Walked the track on Friday... so much history, such a stupid place for open wheel race cars Completely surreal to be in Monaco on race weekend.
Living in London now but with the VISA up in June, I'm trying to decide to either do Monaco again, Barcelona or Valencia before heading back home.