Online vs Local Economic Calculation

So I finally went and bought a pair of the Vibram FiveFinger shoes. I've never tried on a pair before, so I have no idea if I'll like the fit. But I did the math, and am taking a chance with an online order.

With the advent of online shopping, we now have access to sales all over the country, and I found several retailers who had various styles and colors of the shoes in my size (as based on my foot measurement per the online sizing guides). The prices were about half off full price, the reason being that they only had a few pairs available in bright colors. Since I want these shoes for walking out here in the country, I don't care too much about what color they are. If it turns out that I love them so much I want to wear them all the time, I might get my next pair in a more neutral color so they won't draw attention to my feet, but I am not at all sure that I want to really appear in public in these things. These are those shoes that fit over each individual toe, if you didn't recognize the brand.

Since I'm not sure they will fit me comfortably, I wondered whether to buy them locally. But none of the local retailers have them on sale now, so essentially, I'd be paying about $50 extra for the privilege of trying them on if I wanted them, but it would be free if they don't fit. I think it is unethical to try things on locally then buy them from another store online, so I wouldn't do that if they did fit. Since I'd have to pay return shipping to the online store if the shoes don't fit, I'm only going to be paying about $8 for the privilege of trying on those shoes if I don't keep them, but it would be free (and a significant discount from the local store) if they do fit.

So my mental calculation is that I think the odds that I they will fit and I will like them are greater than the odds that they won't fit, and that I'm willing to risk $8 to find out, which is way less than the $50 I'd risk the other way.

The pair I got is black with hot pink, in a model meant for "trekking" which I presume will be suitable for walking over gravel and through fields. I can do it barefoot, but I've found over the summer that it makes my feet rough and I'd prefer they stay softer, and it is very annoying when I get scratches or bug bites on my feet from this. Plus, it will be getting colder, so I want something minimalist to wear when my sandals (I got Teva sport sandals for the first time this year and really like them) will leave my feet too cold. Plus, the scratches and bites are a problem with the sandals around here, I could really benefit from some toe protection.