$6500 is kinda tight, if you live alone it should be enough, if as you say you have a roof and utilities (gas, electricity, ?). Still, as I say, is tight. In some parts of the country the public transport is very cheap, in others is a bit more expensive. And to put things in perspective my family spends more or less $1000 every week on the supermarket, we are four.
If you want we can PM so this thing stays on topic.

that's about right, el peso is falling dowwwwwn.