Local food is extremely cheap. Unlike the other South East Asian countries, Bali has a lot of variety when it comes to vegetarian food as well, especially in Ubud. There are options available at your "Warungs" ( local food stalls) and the food is usually good .I've had food as low as 12,000 IDR at the warungs. Western food is a bit more expensive but affordable at cafes at around 120,000 IDR. And there's no upper limit on that, depending on where you go. I personally love the local Indonesian food so I was practically jumping from one warung to another to try out everything I could. As a non-vegetarian, I'd recommend you to try the Suckling Pig while you're in Ubud, and the "Satays" are a local favorite so give them a try as well. FYI- Indonesian food is quite spicy.
Accommodation Despite being an island, Bali is not as expensive as one would expect. I found accommodation options to be much cheaper than what I found in other south asian countries. I'm a budget backpacker, so I heavily rely on Couchsurfing and Airbnb. There are quite a number of people who can host you via couch surfing in Bali , but make sure you go through all the reviews before you send out requests as it carries a risk of its own. Bali is a paradise filled with beautiful Airbnb villas offering views of the forests and infinity pools . Depending on your budget, you can find a decent Airbnb place for anything between 200,000 IDR to 400,000 IDR per night and beautiful villas to rent above that band. There are lots of Hostels as well where you can put up and it'll cost around 135,000 IDR per night.Bookings.com has plenty of deals every day and if you're lucky enough you can get a good accommodation at a hotel for as low as 1200-1500 INR per night if you keep a watch on the deals.
Places of Interest -
Ubud – is the heart of Bali. It’s culturally and spiritually enlightening and is the countryside of Bali. It also shows you the Indonesia that you never thought could be, by exposing you the rustic countryside landscape of Bali where the volcanoes stand. It’s also the Yoga Hub, and rightly so, it’s a place that will zen you out the moment you step into it. 2 days is enough to cover all the places in and around Ubud, but honestly stay for a week at least to really soak yourself in the culture and ambience of Ubud.