What to look for in a protein bar
Price / Protein per serving
As always, this is usually a trade off between price and quality. When looking at the prices of the different types of protein bars you need to take in to account the percentage of protein in each bar, anf the size of the bar. From this you can work out how much protein you get for your cash. This may seem anobvious thing to do, but is well worth the trouble as some of the protein bars vary massively in size.
Carbs / Sugar
This will depend on the aims that you have. If you are looking to lose weight then you would want these to be low. If however you are wanting to put weight on, then you should be looking for a higher amount per bar. Remember that not all carbs are the same, sugar is generally not goot, where as higher quality carbs are generally good and can help with training.
Fat
Everyone needs a little fat in there diet, but you wouldn't normally want to be getting it from your protein bars. You can have a little fat in them, but usually you would be wanting this to be a small amount.
Summary
So the protein bar that you go for will depend on what you are looking to do with your training, and how much you are wanting to spend on them. You can buy a lot of them in bulk in order to get reduced pricing, and once again, they are meant to be used as a snack / supplement to your normal meals.