I donít know where you live so I cant say regarding travel costs.
Hotels vary from a few $/night up to $100s/night the most expensive I noticed was $150/night.
What most independent travellers do is get to Goa, find an hotel and book 2 night and go look for an apartment for about $150/week, as far as I could see everything is booked on a daily basis. Charter flights are in the region of $1000/1500 for two weeks from the UK.
Taxies are very cheep my taxi from the airport to my hotel an hours drive cost an agreed price of $15.00 and carry up to 4 people
Sight seeing and guided tours are in abundance and easy to arrange, also very cheep a day trip to a spice farm including transport, food and drinks will set you back about $20 I was not to impressed eating curry chicken and rice with my fingers off a banana leaf, but it did taste good, to feed and wash their elephants is extra, about $5 didnít understand that, being charged to do the work of a Mamute (sp)
Food is some of the best I have tasted most restaurants serve Indian, Goan, Chinese and European food and very cheep the most I paid was $16 for lobster. Waiting, well you have to wait for you food everything is cooked fresh, nothing pre cooked or warmed over.
Tipping is not compulsory but expected 10% is quit enough say a meal and drinks for 2 came to $30 a $3 tip is 2 days pay for a waiter.
If you speak Hindi, then half the above prices.