Do you think you really need memcache? AFAIR it needs to be started separately from PHP, so either your hosting server has to have it, or you should have your own VPS or a dedicated one.
memcache is good for big aplication for storing needed information (for example joint sql select), which will be if not cached generated every time requested.
From php site: Memcache module provides handy procedural and object oriented interface to memcached, highly effective caching daemon, which was especially designed to decrease database load in dynamic web applications.