What's so difficult? Create a script off dba_tables, run the script, you're done.

set trimspool on
set pages 0
set linesize 222
spool grants.sql
select 'grant select, insert, update, delete on ' || table_name || ' to apps_user;'
from user_tables;
spool off
<edit grants.sql to get rid of extra stuff>
@grants.sql

If you spend 5 minutes on it, it will be a lot.