Jesse, you raise a couple of interesting issues with your question.
First, with regards to cost... One of the things about traditionals is that they tend to use traditional (older) steels in the blades which, as a rule, are less expensive than many modern "super-steels". I would suggest avoiding the trap of associating price with quality on this front. Many of the traditional steels behave differently than super steels and are often better suited for day in/day out use with the expectation that you'll sharpen or touch up the blade regularly. Traditional steels like carbon steel are "tough" and resist chipping better and they sharpen easier and respond to touch ups on steels or strops. All of this to say that you can find a very durable, high quality and effective knife for much less than your $100 mark.
With regard to box cutting, I've found that cardboard is one of the toughest things on a blade. This is why "box cutters" with replaceable blades are so popular in retail stores. If you're going to use a traditional knife for this (many people do), you may want to prepare, in advance, to learn how to put a quick edge on your blade using a small stone (like the DMT credit card stones), something like the Smith's quick edge tool (people who know will say this roughens up your blade but dang, they are quick) or a pocket steel rod. Back in the day before disposable box cutters, any workman had this skill. It's gratifying to learn this.
Another consideration regarding blade shape as it applies to box cutting, I find that flat ground blades do a much better job than hollow ground blades for things like box cutting. IMO, the shoulder of a hollow ground blade really adds a lot of drag to the cut. I would also avoid blades that have a sharpening indent at the choil of the blade as this can hang up in the cardboard. It causes a tell-tale curl of torn (literally torn) cardboard to peel off when I use knives of this sort on cardboard. This isn't deadly. You can over come it by choking up on the blade, but still, I find it buggy.
In terms of scaring people, I think you will find that traditionals scare people less than modern folders. The one exception are knives with clip blades. I find that the visual reference to Bowie knives is more apt to raise eyebrows. My Buck 112 (clip point) is exactly the same size as my Buck 500 (drop point) but my 500 is a friendlier knife. My Opinel #9 came stock as a clip point and is more people friendly now that I've reworked the blade to a drop point. This comment is more applicable to larger knives with blades in the 3" range. For smaller pocket knives, I find it's less of an issue. Still an issue. Just less.
Lastly, I've found no knife to be more people friendly than an Opinel. I don't know why this is. They're very crude out of the box and you'll need to learn to adjust and tune it up to get good->great performance, but I do find that people are more attracted to them than about any other knife I've carried.
For single blade knives, I would look at either Opinels or Case Sodbusters.
For multiple blade knives, you have a ton of choices. Choose by what makes you happy. I would just steer clear of hollow grinds and sharpening choils.
