Hi Didache,
I was in Krakow a few months ago and really enjoyed my time there. I did do a little tobacco hunting and came across two shops that I can recommend. The first is a shop near the Barbakan Krakowski. Heading north as you make your way to the gate entrance turn right along a narrow street. The city walls will be on your left and half a block down you come to a small tobacco shop on your right. Here's a photo I took when I was there:
And here is an image from Google Maps to help you along:
https://www.google.ch/maps/@50.0647931,19.9415984,3a,75y,84.38h,85.47t/data=!3m6!1e1!3m4!1sN8nr-pQkLDXZ_GP_mcquzw!2e0!7i13312!8i6656
They had a fairly good selection of tobaccos and I picked up a few:
I'd never heard of any of these, and truth be told, I have yet to open them, but the tins were relatively affordable at around $13.00 per tin. The 10 g pouches were $2.00 or so. Definitely need to open these soon and give them a try!
Another place to find some good deals on pipes and tobacco is, and I hate to say it....the mall! There is a Smoke Shop on the bottom floor of the Galeria Krakowska; here's the link: http://smoke.pl/# The prices for the Stanwell and Peterson pipes I saw were comparable to online prices--the benefit here is that you can handle and inspect them before you buy. They had a smaller collection of pipe tobacco but did have in stock G&H tins of Ultimum, American Delight, Broken Scotch Cake, and Louisiana Flake.
And while you've been to Krakow before I'd be remiss if I didn't recommend our favorite restaurant there called Kuchnia u Doroty. Absolutely fantastic Polish food--we especially liked the zurek, bigos, sole in lemon sauce, and of course the goulash with potato pancakes. They also had local bottled craft beer on offer when I was there which was very good as well. Do give them a try if you have the chance! https://www.tripadvisor.co.uk/Restaurant_Review-g274772-d1993331-Reviews-Kuchnia_u_Doroty-Krakow_Lesser_Poland_Province_Southern_Poland.html
Enjoy your trip, and let us know what you find!