As some one else mentions amazon might be one of the best place to purchase your outdoor solar lights. However solar lights can be found almost all over the Internet if you do a search for solar deck lights or outdoor solar lights.
An important thing to consider also is placement consequently it good to have a plan for the placement of your lights and in fact a whole lighting plan is great.
Getting good quality solar outdoor lights which is what you might be thinking of, is more related to the brands you purchase. Some good brands to consider is Westinghouse, a company called firefly makes some exceptional solar outdoor globe lights which I personally love (don't confuse them with firefly magic). There are many other brands on the market so if you are interested to learn more contact me and I will direct you.