Gift to a second-advisor
Barring any specific restrictions in your country or institution, a gift is fine in this circumstance. I'd suggest something small, fairly inexpensive, but thoughtful. I've got chocolates from a master's student sitting on my desk right now and I appreciated them. If you are from another country or region, some treat from your place of origin would be appropriate. Really, just a thoughtful card in which you've written how much they helped you is enough (and greatly appreciated).

I'd not give the hardbound copy unless they specifically ask for it. We supervisors only have so much shelf space and most of us don't have room for all the physical master's dissertations we supervise. I'd personally not want one. Digital copy, sure, but I don't have a use for a physical copy and your supervisor likely doesn't either.