Tootfinder

Gnucash is a nice simple Gtk/GUI accountancy program; I've used it to keep track of my spending, income, credit cards etc for well over a decade; it does simple double-entry stuff and also has some more advanced stuff for generating reports and small businesses.
https://www.gnucash.org/

Free Accounting Software | GnuCash
GnuCash is personal and small-business financial-accounting software, freely licensed under the GNU GPL and available for GNU/Linux, BSD, Solaris, Mac OS X and Microsoft Windows.