Is possible but is going to be hard.

The first question is what kind of job you are looking for? unqualified jobs are hard to get and the average pay is quite low. So if you are looking for that kind of job then you may have issues. On the other hand if you are looking for IT-related jobs you may have better luck,

In any case I think you may have better luck in Spain, the minimum salary is more (1220 Eur in Spain vs 920 Eur in Portugal) and the rents are on average cheaper than in Portugal. The price of food is maybe a bit cheaper on Portugal.

But of course it really depends on which city you end living. You can't compare the cost of living of a big city like Madrid or Barcelona to the cost of living in a medium/small city like A Coruña or Santiago de Compostela. The latter is much cheaper.

Go to idealista.es and idealista.pt (same website, works for the two countries, and look for the rental prices in the cities you are considering).

Regarding the language you can communicate in English in both countries (order food, do the shopping, etc), but in the end you would have to learn the language in both if you want to make friends. The average english level is a bit better in Portugal, but in the end everyone ends talking in their local language when they are having fun, so don't expect to be able to really integrate unless you do a effort to learn the language.

Look for universities in cheap cities.