How is cheaper to travel in Portugal between cities, by train or by bus?

The bus is cheaper, of course. Trains aren't very cheap. An example: while travelling from Oporto to Lisbon by train may cost you around 40 €, you will only pay about 17 € by bus.

Well, in fact both means of transportation are very similar concerning prices. The bus net is much wider than the trains net. Depending on the cities you visit you will probably have problems using the train because it don´t serve all cities.

But I were you I would prefer the the train because you can pass through fabulous and historic train stations.

Use the following link to www.cp.pt evaluate the train Portuguese net.

Use the train if you can because is cheaper if not use the bus, is not that bad either.

Bus.

depends on the distance really, for short distances bus for longer distances train