NEONUS, s.r.o.

This plugin adds a “Pay by Cash” payment method to WooCommerce. It allows customers to choose to pay by cash upon delivery. The admin can configure the display name and map enabled delivery methods.

Pay by Cash for Woocommerce

Simple payment method for cash payment upon delivery.

postpostmodern

Cache Money stores all database result sets on the filesystem as serialized data, by using the oft-neglectged wp-content/db.php to extend the normal $wpdb class. Result sets will be updated as needed on a user by user basis when they do actions that perform update queries.
Please note that this is not a full scale page cache, like WP-Cache or WP Super Cache, although this will work just fine in conjunction. Cache Money is meant for sites with constantly changing content, where a full cache may not be suitable.
Tested with WordPress and WordPress MU 2.8.0 ~ 3.1 
Requires PHP 5, like all good PHP apps.

Pay by Cash for Woocommerce vs WPDB Cache Money