I use shrink wrap bands (open on both ends) on my soap bars and coffee filters on my round soaps. In my area, packaging is the least consideration for purchasing. We are extremely behind on most eco-conscious efforts and practices, so take my perspective with a grain of salt. (Seriously, we got an Aldi about a year ago and the number of people I personally know who won't shop there because they have to bring a bag, find a box in store, or purchase a bag at checkout is very discouraging. It's one simple thing to help reduce one-time use items in the landfill and they think it's a criminal act.) Personally, I consider myself to be leaning green, and I do not hesitate to buy shrinkwrapped soaps. My thought is that it's still less plastic than a bottle of body wash or a bottle of shampoo. Some day if/when I get to the point of "zero" rather than "reduce", it will be a choice that I make for my personal purchases as well as what I sell.
A suggestion: what do you want your soap to be known for? Just good soap? Good soap + eco friendly? If you're selling, sell for what your target market wants to buy.