Yikes, that sounds like someone that's been listening a little too much to the news! There are a lot of cheaper areas that are as safe, or even more safe than Recoleta (remember, Recoleta has seen the lovely return of the quemacoches band... maybe not injuring people right now, but were you to cross them in the middle of that action I wouldn't be surprised if you were threatened). I'm just saying that living in Recoleta or another very expensive barrio doesn't guarantee safety. There are a lot of middle class neighbourhoods that are cheaper and perfectly fine safety-wise. Like any barrio, you need to learn the good parts and the parts to avoid. Cheaper barrios don't mean La Boca or even Baracas, I'm thinking more like Boedo, Almagro, Villa Urquiza, some areas of Chacarita (some are icky at night), Saavedra, Coghlan, some parts Colegiales (because some parts are just as expensive as Palermo/Belgrano). There's a whole lot more barrios out there. 300 USD is 1500 pesos in conservative estimates right now, that's a lot of money. In fact, in a lot of barrios I just mentioned, that would be your rent.
Also, 300USD "compensate for additional travel time", well you'd have to take a TONNE of cabs to even come close to spending that much, so yeah, there's a lot of people out there that would say sure, it will compensate.