Tandy Leather Factory has the best deal right now on their own tool, the Craftool High-Tech Leather Splitter, for $149.99.
Looking around for a cheap way of splitting leather, that is, reducing the thickness of a piece of leather, I found that the Craftool splitter is the cheapest option out there compared to the professional leather splitters that run in the $550-$1000 range. While it likely isn’t useful for a professional leather crafter, it seems like it should work for the occasional leather job within the 4-3/4″ width allowed by the splitter. No mention is made of the maximum thickness, however, nor have I found much about how well it performs.
Craftool High-Tech Leather Splitter [tandyleatherfactory.com]