Lisbon nightlife focuses primarily on one of the oldest districts in the city: the Bairro Alto of Lisbon.
It can be accessed from the center - the Plaza del Comercio, for example - taking a good walk of about 15 minutes uphill or taking the mix between tram and funicular that takes you from the Avenida da Liberdade.
The Bairro Alto is full of restaurants of all kinds and small pubs They offer great deals on all kinds of exotic drinks like kaipirinhas and mojitos, cocktails and beers. In the majority you will listen to Latin music, but there are also punk, heavy metal, gothic and hip hop cut, being almost all full of people who will soon look for some fresh air in the street, causing that there is even more life and atmosphere in the streets that in the same pubs. They will also offer you weed and all kinds of drugs in most of their corners when the policemen - very present in the area - look the other way.
We passed by on Friday for dinner and the streets overflowed with life. We entered a Portuguese food restaurant where we had dinner quite well and it would have even been very economical if it weren't for the rookie trap. Be careful because it seems to be something usual. We ordered our main dishes and the drink and, to ease the wait, the waiter brought us something we hadn't asked for: a few black olives, 4 small pieces of different cheeses and some bread with butter. As we were quite hungry we tried a little of everything. Well, the price of that “entry” that we did not ask for amounted to 20 euros, almost the same as the dishes we ordered. Judging by the angry faces, I think that the Italians at the next table had the joke even worse.
Another night we had dinner in one of the alleys that descend from Avenida da Liberdade towards the Plaza do Comercio and they served us the same thing but here they already told us how the thing worked: you only pay what you touch, and at a much more normal price. In these streets small restaurants also proliferate and most are specialized in fish. Your public relations will assault you to occupy one of their tables.
Don't try to eat at Bairro Alto at noon because the area is entirely dedicated to the night and you will find practically all the restaurants closed.
I recommend you try the fish that Lisbon and, specifically, its typical sardines. You can eat well and cheaply, it is a thing, as always, to look a little and try to get out of the typical tourist route.
The Barrio Alto is not the best example for this purpose but if you fancy a good march after dinner, it is certainly best to do it there.
The truth is that he loved the area because of the great resemblance he has with the Barrio de Alicante. The old town crowded with small pubs that was my "home" for so many weekends and I still return whenever I am in my city.