Q. What can be an expected budget for 1 to explore Sonajhuri for 3 days including food, lodging and doing all that can be done there to enjoy that place??
Kolkata is a suburbaner's paradise as there are multiple places you can visit around the city for a quick day trip. You can go to the beautiful Raichak on Ganges, which is 55 KM approx from Kolkata. (Read More)You can also visit Arambagh, Tajpur, Mukutmanipur etc. For more info, check out this blog by Holidify for the best day trips around Kolkata - http://www.holidify.com/blog/best-day-trips-from-kolkata/.
Hope this helped. :)