Suggest going to Best Buy and looking at a few. They have numerous in the <$500 range that will do want your wanting. With your needs mainly being a built in camera (most laptops have this now) for video calling, storage for pictures (bigger hard drive the better), after verifying the ones you look at have those things, I would focus on the one with the most memory and processor speed. Processor speed is the engine, how fast the computer will process things, Memory is "fast storage" for when your opening multpile pictures or applications.
Get one of the young guys there to help you understand the differences between models (they love sharing their knowledge about this stuff) and they will help you get something that you will be happy with.
One last suggestion is ask about a 2 yr protection plan. For something in this proce range, it may be very affordable. If nothing else, it allows you to take you battery back and get a new one simply by stating it won't hold a charge for very long as you approach your two year anniversary. If anything else happens, you have an additional year on the normally one year manufacture warrenty.
Usually around $99. Subtract the cost of the new battery and your getting the extra year of protection pretty cheaply.