Stippier do not worry about it. Nice to have new people. what charger do you have?
This is the order I would buy. Make sure you buy protected batteries.
You could go for XTAR 18700 2600 mAh Li-Ions group-buy for $13.50 shipped to you but these are very long and may not fit your charger. Email them they should still sell it at that price.
Protected TrustFire 18650 3.7V 2400mAh $10.89 I have 3 sets of these.( Look aroung you can get them for less than $10)these are good and a newer version Protected TrustFire 18650 3.7V 3000mAh $11.70 but some say that they are only 2400mAh other s say 3000mAh.