3 month rental

And how much would that be in €? This is the Western Europe board, no country covered under this branch uses the $ (= Mexican pesos, Hongkong dollars?) so it would help if you convert your budget into local currency.

That's about 500 Euros.

Do a search on Portuguese newspapers and check the classified ads. If you speak Portuguese all the better, in terms of your search results. I read ads for apartments, which ranged from about 450 e/m upwards. That was the best that I could find when seeking similar arrangements.

Thanks. I did find one English-speaking newspaper and they have a few rental ads, with phone numbers. Though I have a strong feeling that I'm missing out on most of the rentals by not speaking Portugese. Ah well....

I have a strong feeling that I'm missing out on most of the rentals by not speaking Portugese
Then how about learning some Portuguese? Or do you expect all the people around you to speak English to you in those three months?

Hey Arbo I think you are assuming an attitude where there is none. I speak pretty good Spanish, good enough to get by in Central & South America a few trips. I certainly plan to "pick up" as much Portugese as possible WHEN I'M THERE. Maybe you should try reading the classifieds in, oh let's say Finland, and see how easy it is.

Phil, I think I did indeed read too much in your comment about missing out on a lot of information because you don't speak Portuguese - I've heard similar comments in my own country way too often from foreign residents who never bothered to learn my language and take it for granted that all locals speak English to them, a fact that annoys me pretty much. That does, of course, not give me the right to take that feeling out on you, so I'd like to offer my sincere apologies. I hope you'll be able to find the kind of appartment that you're looking for.

Apology accepted and much appreciated, Aribo! Yes, many Americans think we are the center of the world. This attitude gives rise to many misconceptions - an ignorance masquerading as arrogance. The politicians of course are only too happy to exploit these shortcomings, turning them into fears. But I digress.... We are currently looking at renting kitchenettes by the month in hotels....

Take a room in the youth hostel in Lisbon and from there look for a room. The people there will help you with some advice. You also need to know where you want to be. Some places are more expensive than others. Lots of Portuguese in Lisbon speak English.
You might consider placing an ad in the weekly newspaper "expresso" or in the advertorials paper called 'jornal Ocasiao", Someone may help you read the ads in this paper. Place your ad only when you know what you want, so you get the response you need.
To find a room is easier if you are a couple or 2 women. But consider that rooms are pretty tiny and so are lots of houses, so no much privacy.
For an apartment 500 euro might be enough to cover the rental price but you still need to ad the extra costs of energy (gas, electricity) and water.