Ugh, the dangers of posting late at night: the title should read "in" not "on" Porto and Lisbon. Time for some shut-eye.

In Lisbon I suggest you look for deals in the Avenida da Liberdade area. This guide to that avenue/area of the city lists a few hotel choices there: http://www.lisbonlux.com/lisbon/avenida-da-liberdade.html

In Porto, this site recommends a few within your budget, most in central locations: http://www.gooporto.com/porto-hotels/

In both cities you'll find that there are good 4-star hotels and other good choices at around 60-80 euros per night, especially during October.

Thanks, these websites are great.

We were in Portugal in November for 2 weeks and loved it. We always rent an apt, particularly for the washer/dryer. Had a fabulous one in Lisbon from www.homeaway.com #233888. Much better than pics and owner is fabulous, helpful and responsive. Extremely large apty with large LR, large DR,, large bedroom and nice kitchen and bath with tub.It was wonderful. Fab location with bakery, grocery and butcher right there and trolley runs in front of apt.

In Porto, we rented #432234, IF and again it was great but a studio but in a great location. Owner came by mid vist to see how were were doing.

Can highly recommend both. jk

In Porto we recently stayed at the trendy Porto Trindade, walking distance from the centre and with good bus/metro connection to get back (because it's very uphill). Rooms a bit smallish but very clean and excellent breakfast included. Very friendly staff. Ask for a room facing the back because the hotel is on a busy street.
http://www.hotel-portotrindade.com/

In Lisbon we stayed at Residêncial Florescente Hotel.
Very convenient accommodation near Praça do Rossio and Praça dos Restauradores,near train and metro station, on pedestrian street. Free Wireless Internet access, air con, breakfast buffet. We paid 60 Euro / night

In total agreement with valtor. I stayed at Florescente last January for 5 nights (it was 35 euros during low season), and loved the convenient location and everything about it!