You guys are really something. An obvious novice comes on here asking about a beginner system and you have to show how superior you are by changing the subject to SiO2 Batteries without even telling the guy how they would be of great value to him. Only to you.
To the OP: The Harbor Freight or any other "Kit" may not be the best bang for the buck, but for pocket change they can introduce you to solar. Within minutes the kits can be providing enough energy to charge cell phones, etc. which is what you asked about.
As far as batteries, most Walmarts stock Group 27DC batteries (The DC stands for Deep cycle, not Marine starting) One 27DC has 109 amp hour rating. two have 218 AH which is almost exactly the same as 2 6 volt golf cart batteries at 220 AH. The advantage? The 12 volt batteries can be used as singles, doubles, triples and so forth with simple parallel wiring, not the zig zag and multiples of two required for the six volt units. And don't let the so called exerts turn you off on solar with their bragging. It can be fun, educational, and practical.