Big cost savings can be made with a walk-in pantry. By having a separate room and door, there's absolutely no need for cupboards and cabinet doors within the pantry. Think of the pantry as a cupboard! Bench tops can be practical and not showy - you don't need Corian or Caeserstone surfaces. A walk-in pantry is a separate room, so soft-close drawers to keep noise down aren't necessary either.
Ours has a two-way swing door, which we love. We probably should have bought a door with a window to avoid the risk of bumping someone with the two-way swing action, but we'll live without it. There's also an electronic "instant on" fluoro light, with sensor and timer, so that there's no need to be scrambling for the light switch when entering or leaving it.
Having moved in only a week ago, we propped the swing door open on many occasions when stocking the shelves, so in hindsight a hook or magnetic door stopper would have been handy to hold it open when constantly accessing the pantry. We're using an ornamental door stopper.
Our pantry has quite high shelves. I'm 5' 11" and can only just reach the top shelves. All our shelves are adjustable, but we still have high ones and a step ladder is handy. If you'll need a step ladder, give some thought to its size and where you will practically store it so that it is handy when needed.
We have two double power points (GPO) on the bench, and will have a third fitted shortly. Although we don't need it, at the same time as the extra power point is fitted we're also having a power point for (LED) under-shelf lighting fitted, over the work bench. We're finding that with the long fluoro light, white ceiling and white shelving, the pantry is quite bright. However, if we change our mind we'll have provision for the LED lighting over the work surface later.
Finally, think about shelf depths. Shallow shelves mean it is easier to see what is stored on them - no more losing items at the back. Our wide shelves are being used for appliances, bottles, etc and the foodstuffs are on the wall of narrow shelves.
For more views of our pantry see this post.
I wish we'd also bought the book The Pantry: Its History and Modern Uses for about AUD$12 (+ postage) before we designed ours because it might have been even better!