Hey,
Goa is an amazing experience to go for with your crew or loved ones. A few suggestions to save money would be staying near Maupsa which has cheap rented flats and major beaches are pretty close as 10 mins drive.
Also, if you want to try scuba diving don't go for Anjuna beach try visiting tarkarli while returning from Goa you will enjoy water sports more there. The best part of my goa trip was Club Cabana. Don't forget to visit it.
Have a great trip.