It seems like what you're looking for is an OD which doesn't add much compression. It's easier to find that spot on an amp- the problem is volume; but the way it works with most pedals is that as soon as you engage the pedal it automatically squashes your dynamics, regardless of how much gain you have dialed in.
With a $100 budget, I'm not sure how many pedals you're going to be narrowing down to and still getting what you want out of it. I sure as hell would not want to spend any money on a Chandler Tube Driver. The pedal I've been the happiest with is a Barber Direct Drive. It's a little out of your budget (I think around $112), but I believe it's a great pedal. The new ones have the LED placed in a better spot and have more low-end response- which is a little lacking in mine.
The best advice I can give you is to ignore all the intArweb hype regarding pedals, don't expect a pedal to do what it cannot do (sound "just like" a "Marshall in a box"), try as many as you can get your hands on and figure out what works within the context of what you're looking for, and not what people think you're looking for. There's plenty of people that think the Ibanez Tube Screamer is the cat's pajamas- for a reference on that sound- think Stevie Ray Vaughn. I hate his tone, I hate how compressed everything sounds. I remember getting my hands on a few different TS-9 and TS-10 pedals and being confused and disappointed- "everybody loves these things- but they SUCK." Remember that other people may be looking for something entirely different- regardless of how well you try to explain yourself.
Aren't things easier when you can "play well with others?"
