I am off to Portugal for Oct/Nov and was happy to see there is a ELMS (or whatever the series is called) just along the road at Portimao while I'm there. And they've now gone and announced a grand prix there the previous weekend!! I hope they aren't behind closed doors. The ELMS race is only about €10 for the weekend!!
EDIT: The official Portimao web site just has an ad at the moment so you can't reach anything but the ELMS site says it'd behind closed doors :-( Which probably means the F1q will be too.
Went to Portimao 2 years ago for the ELMS.
Great circuit, little access around the track, but you can see 75% of the track from the grandstands, hope you have a head for heights.
It was free to get in, €10 got you paddock access.
I have read a report that the F1 will allow spectators, didn't say who or how many though.