The local tour buses were very good Red Bus and Green Bus used, took some time to get started as they wanted to fill the bus, however it did cover the main tourists sites and was hop-on-and-off. On reflection with better knowledge using the trams would have been cheaper however with no commentary on public services research in advance and a good map would be essential.
Lisbon is hilly, so use the trams to go up the hills and walk down. The City is one of contrasts, with some areas requiring regeneration and others with designer shops and homes.
Certainly a port you can do on your own if you want to reduce costs.