Answers

The small walk in pantry will be the less expensive option. However, having a cabinet that functions as a pantry is often a better use of space and ends up as the more preferred option by my clients.

But it's all about you (or your client)! What would you/they prefer? Is the storage space best utilized with just simple open shelving? or would it be organized best with pull-outs and drawers? There are obvious pros and cons to each, in my experience - the extra cost of a cabinet wins 90% of the time.