Like everything else in Portugal right now, it's very expensive. Without the residents discount from the Dona Filipa it's 150 euros per round.....
San Lorenzo build up a fantastic reputation over a couple of years, to the point that it was rated one of the top courses in Europe. It's been living off this reputation for a while and the course has been declining in quality for a few years. It's still an excellent layout, with some brutal holes when the wind blows (6,7,8) but it's just not as well looked after as other top quality courses.