As with anything the first question is how much money are you about to spend?
But that said if you go the fixed blade route I do have a suggestion that won't break the bank. If nothing else you can try this and if it doesn't work for you, you can do what I did and trade up.
First the knife. I reccommend the CRKT Companion or Plan B. They're both inexpensive but not junk. At around $25 each give or take they pass what I call the drop test. Can you drop it and forget about it and not agonize over it? Yes. The other thing is that if you find there's something about the knives you don't like, you aren't out a war pension.
Now the most important thing when carrying a fixed blade IWB is the sheathing and the factory sheathing for these knives is awful. They should just sell the knives by themselves because the sheaths CRKT gives you aren't even functional. I personally recommend you spend the $30 or so to get a sheath made by On Scene Tactical or some other sheath maker.
You can find info on the knives easily enough, but here's On Scene Tactical because they're a little hard to find:
Now if you go the folder route, I personally recommend the following products and I tell you why. First they're not super expensive so if they don't work for you, you aren't out a big load of money. Second, almost everyone likes them a little bit at least so you'll find another use for it even if you don't like to carry it, kind of like what I've done with my P89. Third I know first hand they are good knives that would last you a lifetime if cared for properly.
My personal favorite entry level folders are the Spyderco Endura and Delica. They have trainer models, they aren't super expensive, they're just fantastic knives. There's a little knife for the people that like the little knives and a bigger knife for people that like the bigger knives, they have multiple models with movable clips that carry different ways, so everybody's happy. There's a reason they are Spyderco's flagship product.
Now some people don't like Spyderco and think they're weird. Personally I'm a mindless Spyderco slave but that's just me. It costs a little more but I think the Benchmade 550 (hole) or 551 would be very much to the tastes of people that don't like Sypdercos. It seems you're either a Benchmade person or a Spyderco person.
A third alternative that's pretty common and not too expensive is the Kershaw Vapor and Vapor II. It comes in the smaller and larger size, and it's just a great knife for the money. It's also cheaper than the other choices I mentioned.
The thing to realize is that knives are like guns only much worse when it comes to subjectivity. The little debates we have here on revolver vs. semiautomatic or 9mm vs. 45 ACP are not nearly as divisive as people's opinion's on knives. I personally have a knife fixation and I went through a lot and I do mean a lot of knives before settling on something and I'm still not done.
I would say though that I've found around $25-$30 is what you have to pay for a knife that's "good", for whatever that means. It just goes up from there. Personally my glass ceiling on knives is usually $100 because I feel that if you spend any more the returns on your investment just aren't worth it. You can get such a good knife for $100 I just don't see the point of spending any more because the difference between a good $40 knife and a good $100 knife is pretty small sometimes, and the difference between a $500 knife and a $100 knife is even smaller.
Don't get me wrong I'd crap myself in joy if you gave me a Sebenza or a Strider, but I just don't need a knife that is that good. It doesn't offer me anything that I feel like I honestly need.
My personal choice in a carry blade is the Spyderco Perrin Bowie, and in a folder the factory waved Endura or the Manix. But I'm a Spyderco nut.