Running CiviCRM 5.22.0 with WordPress 5.3.2
Whenever a user attempts to create a membership AND record membership payment AND send confirmation and receipt, an Invalid currency "$" error is generated. The membership and contribution are recorded in the database, but no e-mail is generated. CiviMail is working in all other contexts.
If a user creates a membership AND records membership payment but does NOT check "Send Confirmation and Receipt?," the transaction completes without error. Editing the membership and selecting "Send Confirmation and Receipt?" will generate the invalid currency error.
I enabled debugging and backtrace and the error displayed with the exception trace is:
CRM_Core_Exception: Invalid currency "$" in <docroot>/wp-content/plugins/civicrm/civicrm/CRM/Core/Smarty/plugins/modifier.crmMoney.php on line 35