I went to goa for 5 days and the overall expense was 8000 INR.
Rent scooty on weekdays before 9 Am , if possible use public transports.There are many small hotels one cam reside.
First of all it depends which part of Goa you want to cover, number of days, how many people ( Sharing reduces the cost drastically). North goa is a bit cheaper than the South Goa. You want to go on budget travel 1000-1200 you can manage