New, crappy furniture is expensive here- but antiques are an incredible bargain.
I have found that for the SAME PRICE as ticky tack mock Ikea put it together yourself stuff from EASY you can buy handmade antiques that have already lasted 50 or 100 years, and would cost a fortune in the USA or Europe. Real wood, stone tops on mesas de luces, carving, inlays, stained glass, crystal and bronze- there is tons and tons of this stuff in BsAs, and since the current tastes among the wealthy Portenos' is for modern Italian design, its low priced. I have found craftsman style pieces, art deco, art noveau, french provincial, 50's space age, and more- stuff that movie stars in LA pay tens of thousands for, dusty and unloved in Argentina, because its out of style and, well, OLD.
The best craftsmen from Italy, Spain, Germany, France, and Belgium immigrated to Argentina 100 years ago, and made stuff to last. Particleboard, eat your heart out.
I second going to the Pulgas- good deals on a real range of stuff there. New stuff every day. Easy to arrange delivery, trucks are standing by. And the whole neighborhood around it is full of more stores. There are demolition shops on Cordoba with flooring, windows, lighting, anything from a 100 year old apartment. I once saw an entire, 10 meter long, 4 meter tall, cut glass and hardwood cafe storefront that would not be out of place in a fancy coffehouse in Vienna.
Way up Rivadavia are two of the biggest antique stores I have ever seen- not dirt cheap, but sure not expensive, with floor after floor of amazing stuff.
La Rueda - Antiguedades
is fancier, and then down a block and across the street is this other place that is kind of like going into the warehouse at the end of Indiana Jones- dusty stuff receding into infinity, 3 or 4 more floors upstairs they will only escort you to if you ask for something specific, with enough furniture stacked up to fill a thousand houses.
Great midcentury design, 50's pieces, at a fraction of the cost in the USA or Europe (but still not giving it away) at Bauhaus in Palermo Viejo.
The guys at La Mersa pick and choose the best stuff, and charge a bit more for it.
La Mersa
and down a block on Honduras is another great antique store, more classical, I think its called Casa de Honduras- amazing crystal chandeliers, art noveau furniture, cheaper than San Telmo.
And dont forget Mercado Libre.