The thank you page (Complete.tpl) will need to echo the order total. If a client orders a server for $19.99 it will need to spit out 19.99 If you can't complete this project on time and with good communication don't make a bid. I've already been burned by a bad freelancer once already. This needs to be done without access to our production WHMCS system/files. I can provide the Complete.tpl though.