$4500 pesos ball park a month, you should be fine on that (excluding rent). Generally you spend more when you first arrive as you are getting used to what is expensive and what isnt and everything else, but if you stick to your budget I am sure you will be fine. Someone made the point about whether you cook or not and that is quite valid, try and buy from the supermarket where you can.
The other Ill mention is public transport. Its ridiculously cheap here, while taxis are still cheap but relatively so not as much. You should organise a SUBE card when you get here (just need your passport). Subtes are about US60c a ride and buses are US25c approx. I would also suggest grabbing the GUIA (transport guide), they often sell them on the subte and you can find people selling them on the street as well. I think they are about 10 pesos (from memory). Also suggest using www.comoviajo.com which is basically a travel planner (public transport) to get your from A to B using public transport.
Good luck!
The other Ill mention is public transport. Its ridiculously cheap here, while taxis are still cheap but relatively so not as much. You should organise a SUBE card when you get here (just need your passport). Subtes are about US60c a ride and buses are US25c approx. I would also suggest grabbing the GUIA (transport guide), they often sell them on the subte and you can find people selling them on the street as well. I think they are about 10 pesos (from memory). Also suggest using www.comoviajo.com which is basically a travel planner (public transport) to get your from A to B using public transport.
Good luck!