Macri is letting the peso float now - as i understand it he's not making adjustments and trying to keep it at a "reasonable value" like Cristina was trying to do. It's the market that's setting the price. I don't think he's spent a centavo or a dollar to try to influence the market (well, the Central Bank, not Macri personally or as executive).
The market is the market - absent other influences (like a bat-crazy she-devil in the Pink House, for example) the value is what people/countries/businesses will pay, for the most part, in conversion. Absent inflation caused by too many pesos on the market, prices will eventually stabilize and in some cases (though probably not with most imports) go down. With dollar investments coming into the country (which get converted to pesos and the dollars stored in the central bank, or spent as currency if people accept it), the value of the peso should hold (at least, I believe that's a large part of what Macri's trying to do).
The peso hasn't stabilized because there is a lot of uncertainty still. The spike in inflation was caused in a large part by people raising prices in fear - a left-over form good ol' Cristina's doom-saying over what would happen if the Dictator Macri gets into power. At some point that unreal raising of prices has to settle - a product is worth what it's worth and absent inflation some of the prices (at least locally-produced like food and other items that don't depend too much on exports) should come down. Keep in mind, one of the reasons to sell food, for example, out of the country, is that Argentina has a lot of farmland and capacity (which Cristina managed to shut down), but the prices they are going to export for can't be too crazy because it's wholesale, and if they raise the prices too much on exports and don't want to sell locally because of this, no one will buy internationally either (or at least not as much). It's not like Argentina has a corner on the commodities market after all.
At least that's how it seems to me. If Macri is successful in defeating inflation by making the country more investment-worthy and productive, inflation should come down. Macri is shooting for 20-25% inflation by the end of the year. I'm betting the official rate will be closer to 16 than to 17 by the end of the year and we will see prices begin to stabilize. But things will still be expensive.
