First determine which needle is going to best for your application. As you mentioned, you will most likely be doing it for sampling and listening as opposed to scratching, if that is the case, get an elliptical style needle. Although they typically are going to cost a little more, remember, we all want the music to sound good, otherwise, what's the point in even listening to it
Ortofon has some decent ones that start around $30, depending on what tables you are going to slap them on. Here's a little cheat sheet on what to consider when needle/cartridge shopping:
Spherical needles
1. Pros: They are cheaper to make.
2. They are the more popular choice of needle (see point 1).
3. They have a lower drag, due to smaller contact area, and this makes them better for scratching.
1. Cons: Higher record wear, because of lower contact area (the smaller the area, the more pressure).
2. Less of a high frequency response, also due to lower contact area.
Elliptical needles
1. Pros: Larger contact area, therefore less pressure, therefore less record wear.
2. Better high frequency response, due to higher contact area.
1. Cons: More expensive to make
2. Not as popular as spherical needles, you're not likely to find them in a club setting (see point 1).
3. Higher drag because of higher contact area. Not a good choice for scratching.