Flights
Good deals RT are ~500-600
On August 12th is a comparable 818 for 2 weeks earlier.

Best price so far is ~770, one way, but August 26.

Potential places to live:
Must haves
Places with co-working cafes are critical
2 BR
Must nots
Over €1.2k/month(?), so probably not Lisboa / Porto
Big cities
- Lisbon
- Porto
- Sintra - mountainous city, Brennan suggestion
Mid size cities
- Braga
- Coimbra
- Costa da Caparica
Resources:
Choose mid-size cities - reddit
Best spots for Portugal - website
Another best cities for DN - website
1 (year/month) trips - website
TT guide on PR - blog