LimeWire is a popular P2P client which uses the Gnutella network. Unfortunately, it limits the amount of ultrapeers to whom connections can be made, in effect reducing the amount of search results and the number of people from whom downloads can be made. LimeWire only removes these limitations if its Pro version is bought at the cost of $35.
As LimeWire is open-source, several forks of it exist. One of these forks is called FrostWire, a client which appears and works in a similar fashion but removes many limitations of the free version of LimeWire. FrostWire also has some features which LimeWire Pro lacks, such as BitTorrent support.
Unlike LimeWire Pro, FrostWire is completely free to use and download. FrostWire is based on LimeWire’s Java engine and as such, it works on OS X, Linux and Windows, providing Java 1.5 or above is installed.