We stayed in Recoleta neighborhood, and if you're comfortable carrying cash you can get some fantastic deals. I had hotel front dest request blue dollar exchange to be done at hotel and you receive over twice the official exchange by doing so. Example if you use a credit card the official exchange is around 35000 pesos for 100 u.s. dollars, but the blue exchange will give you over 78000 pesos, over twice the spending power. We were getting an excellent steak dinner with wine and desert for around 20 u.s. dollars for 2 people. They take crisp no tear or dog eared dollars in 100 dollar increments.
P.S. the dollars are the same its just the name for black market exchange which is an accepted and practiced openly there. You will see them on the streets but I recommend doing it at the safety of you hotel.