There are lots of differences between cigars made by the same manufacturer. Size, filler, wrap, aging, draw, etc. You can't learn enough in a week to make you an expert. Expensive cigars can be worth the price - if you know why your paying more. In your case, I suggest not spending more than $6 or $8 per cigar. Don't buy in bars, airports, hotels, etc. Those are usually overpriced for the quality. Find a tobacco shop. The people there can pick a cigar for you. They usually have the best recommendations for the money.
If you're bringing any back with you, take the wrappers off. That way it will be hard to tell what they are or where they came from.