You can travel to Goa from Delhi either by flight, train or car. I'd say that if you are planning to keep your trip to Goa within a tight budget, you can visit this beach destination via train. If you'd like to travel via flight, you can find direct flights from Delhi to Goa. You can find a round trip flight for anywhere between 10K to 20K per person. If you love adventure and would like to enjoy some scenic views on your way, you can embark on a road trip from Delhi to Goa. Goa is at a distance of 1877 km from Delhi. And finally, the cheapest way to travel to Goa from Delhi is via train. There are direct trains available between Goa and Delhi such as Trivndrm Rjdhni which leaves from Hazrat Nizamuddin Railway Station and drop you till Madgaon for as low as Rs. 760 (sleeper class).
Take the train,stay in cheap hotel, foods and drinks aren't much costly.. Assam to Goa 4days in goa 8k was all i need to cover up but i suggest you to take more money 10k to 15k will suffice with water sports.