Yes, there are solar pond pumps available. You can find them at Pond Depot (http://www.pondepot.com/solarpondpumps.html) or Foster and Smith Aquatics (http://www.fosterandsmithaquatics.com/pond-supplies/solar-pond-supplies/ps/c/5163/14783). Amazon.com also sells pond pumps.

SiliconSolar, FountainFengShui and Pondepot all offer solar pond and solar fountain pumps and complete kits. Target offers a SunJet solar fountain pump for ponds at just $70.

There are several companies that manufacture and sale solar pond pumps. One of the best in the industry,and the one I would suggest is Smart Solar.

Yes, in fact there are solar powered pond filters. This is a good idea to get, because it saves you money in the long run.

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Dependent on size and quality you should be able to get basic models for as little as 40$ (e.g. the Instapark 5 head Solar Pump Garden). For a bit more (100$) you get better models such as the Solar Fountain 8 Watt Pond Water Pump.

Basic solar pond pumps generally come in a price range of $ 40 to $100 depending on the brand and performance. A search in the online shopping sites yielded the following price range: 1.3-watt Solar Fountain Pond Water Pump-$57.99; Instapark 5 Head Solar Pump Garden Fountain Pond -$39.99; Smart Solar Sun Jet 150 Fountain Pump 2 stars (4 reviews)-$69.99; Solar Fountain 8-watt Pond Water Pump Panel-$95.99