Conservation first, and solar hot water second. But I assume you're asking about solar electricity.
If you're ideally located, there are some companies that will lease you panels so that your out-of-pocket expense is not much. Solarcity is one of them, and Akeena also has a plan with as little as $1000 down, supposedly. But that involves a commitment to buy the electricity from them at a fixed rate for a number of years. Understand that for the first few years, this will actually cost more than the electricity you're buying now, and depending on location, may always cost more.
The conventional way to go solar for electricity is to buy the system outright. It could be a good financial move for the long term, but won't pay off for years. Kind of like planting a Pistachio tree. For many years you get nothing, then it finally starts bearing, and keeps going year after year. If saving money is your chief concern, you need to run the numbers very carefully.
Oh, and beware of scams that say you can power your whole house for a few hundred dollars. From the complaints I've seen, they take your money, give you vague public information that is impractical, and refuse to honor their guarantee, not even answering emails after you've bought. If it were easy and cheap to do, wouldn't we see at least a few houses with homemade solar electric panels in the neighborhood?