There are a few on guardia vieja that are pretty good. They are full from about 9pm, perhaps because they are cheap and offer half decent food. They could be benefiting from the high prices in Palermo. You can still get a Ltr of Stella for 30 pesos.
There used to be a bar on Medrano, close to Guardia Vieja, where you could get a liter of Stella for 20 pesos. Unfortunately, it changed ownership a couple of months ago, and I think the prices went up. They also close early now.
That area of Almagro has some of my favorite bars in BsAs.