Maison du Monde, located at Av. dos Cavaleiros, 2790-045 Lisboa, offers decent-quality real wood furniture. Their phone number is 304 500 221.
If you’re looking for something more custom, you might want to check out F. Cardoso e Filhos; although their website doesn’t showcase their work very well, they’ve been recommended for being good and reasonably priced. You can find them at https://www.fcardosoefilhos.pt.
Additionally, consider exploring secondhand furniture groups on Facebook or local thrift shops, as you may find unique pieces at affordable prices.