you need a pen, paper and to draw up a list of things you will need and rank them according to importance and cross reference it with costs. I've done $100 for a month and im a dedicated meat eater, and we all know that is more expensive. i'd recommend divvying up the funds for either weekly or biweekly shopping for budget purposes.
Looks like you'll be living on rice and veg. Fried rice, paella, vegetarian curries, curried rice etc. All of which can be made in bigger batches and frozen for another date. (Just make sure that when you reheat it reaches over 75°C otherwise you risk food poisoning ) soups are also a good idea.