1x > 1x PCI-E cables, but with the data-side filed off to be open-ended to allow plugging in cards wider than 1x, such as graphics cards. They are electrically the same as 1x > 16x but cheaper and much easier to plug into a graphics card. See this picture. https://dl.dropbox.com/u/9768004/risermod.jpg
PCI-E to PCI-E power plug splitters, such as this http://www.newegg.com/Product/Product.aspx?Item=N82E16812198018
Supplementary 12v power that plugs directly into an available PCI-E slot, such as this product. http://www.evga.com/Products/Product.aspx?pn=100-MB-PB01-BR
Lower prices.