I've seen the work they do at the place in Navarette people talk about and it is impressive.
Since I'm in the middle of furnishing my house I let you know what I have done:
I got a living room set made of bamboo from the side of the road on Autopista Duarte for about 150 bucks, had it specially stained a little darker than the blonde bamboo so it would look "different" then I drove up the road to la Cumbre and bought a big flat rock for a table-top.
The more you shop those little roadside places on the way to SD the more you want to just go crazy with the whole "Tipico" theme, but to mix things up I'm getting a bedroom set from Hache, it looks like they may be getting some stuff in from Ikea. It's not exactly cheap, but it is cheaper than buying abroad and shipping yourself.
La Sirena (Pola) has some pretty inexpensive furniture as well, got a few pieces there, and found some nice curtains there as well.
For your electro-domestics you should shop around, Nedoca, Samsung and LG appliances seem to hold up well here and you should compare pricing between PriceSmart, Plaza Lama and Dist. Corripio, as well as La Sirena, El Encanto etc.