GNUCash is opensource accounting software.

This requires the following additional software, and it is suggested
that you build them in this order:

slib libofx ORBit2 GConf libtasn1 gnome-keyring gnome-mime-data libbonobo
gnome-vfs libgnomecanvas libgnome libbonoboui libgnomeui libgnomecups
libgnomeprint libgnomeprintui gtkhtml goffice

aqbanking is optional, but it's not available at SlackBuilds.org.
