The budget will vary depending on what kind of accommodation and way of travel you choose. Remember that Goa has no Ola and Uber. (I know it's sad). The taxi services here are quite expensive. I would suggest you rent a 2 wheeler or 4 wheeler depending upon how many of you are visiting. It is way cheaper.
Apart from this, Goa has several other activities that you can indulge in. There are numerous small and instagramable cafes you can visit for a once in a lifetime experience.