I need to pogram my tpl-add.php file - repost 2

I have a responsive classified website thrue wordpress. I need my website to be able to charge in cents. Like .10 .15 .25 .50 .99 The only way my site will show a payment option for my customers is if i charge $1 or more. If its less than a dollar it will not show a payment method it will just allow the listing to post free of charge. Im not a prgrammer as i know nothing to that. I am just clued as to the suspected file: [login to view URL] and the suspected variable handling function: is_numeric. Im not sure if this is the problem and if it needs to be changed so it can understand decimal. like .25 From my point of view as a non programmer the task seems some what simple to an expert. As in not to much re-writing in code. But i could be wrong. Please be gentle with the price as i have not started profiting from this site.. It is a Starting project.