Traveling to any place in the world would require you to at the very least ask about what ethical considerations you should be making as you move through that area. Things like the tipping culture of that particular space as well as the kind of things that you need to focus on in terms of your interactions with people are really important as well once all has been said and is now out of the way. One thing that you might want to know about if you are thinking of traveling to Kolkata is whether or not you can haggle.
Haggling can be a really great way to get items for a lot cheaper than might have been the case otherwise, and many of the travel agents in Kolkata are going to encourage you to try and take part in this sort of thing so that you can see just how hospitable Kolkata people tend to be on a regular basis. The key to haggling here, especially if you are a western tourist, is to try and offer half the price you are being offered. Many of the stall owners and vendors would appear to balk at this sort of thing but they would only do this to try and guilt you into paying the full price even though it has been driven up quite a bit.
If you feel like they are not going to give you the price that you are asking for, you can always try the time honored last resort of anyone trying to haggle: the walk away. Start to casually walk away and if the vendor is interested they will call out to you and give you an even better price.