Unfortunately you cannot alter or change the text on the PayPal Checkout Screens however, I believe there is a work around. By allowing the patient to input an amount on your web page instead of the on the PayPal Checkout Screen, what they see on the Checkout Screen will be a little different. The online button creator is a great tool as you can generate basic code in a snap however, sometimes you need to take a different approach and manually create the code. For learning purposes, see the example below - it's intended for people to pay their bill online and uses the Buy Now button command. You can even get creative if you're into creating scripts as you can make the fields required but, that lesson is for another day.
<!DOCTYPE html>
<html lang="en">
<head>
<title>Buy Now Button Example</title>
<!-- START META TAG SECTION -->
<meta charset="utf-8">
<meta name="description" content="">
<meta name="keywords" content="">
<!-- END META TAG SECTION -->
</head>
<body>
<!-- START SAMPLE CODE SECTION -->
<!-- PARAGRAPH 1 -->
Pay Your Bill Online Examples
<br><br>
Buy Now - Customer Enters Amount, very simple.
<br><br>
<hr align="left" width="50%" noshade>
<br><br>
<!-- START CONTENTS -->
<!-- START BUTTON EXAMPLES -->
<form target="_self" action="https://www.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="on0" value="Customer Number">Please Enter Your Customer Number:
(Example: 99999999)
<br><br>
<input type="text" name="os0">
<br><br>
<input type="hidden" name="on1" value="Invoice Number">Please Enter Your Invoice Number:
(Example: 99999999)
<br><br>
<input type="text" name="os1">
<br><br>
Enter Amount Due :
(Example: nnn.nn)
<br><br>
<input type="text" name="amount">
<br><br><br>
<input type="reset" name="reset" value="Clear Selections">
<br><br>
<input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_paynowCC_LG.gif" border="0" name="submit" alt="Make payments with PayPal - it's fast, free and secure!">
<img alt="" border="0" src="https://www.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1">
<input type="hidden" name="cmd" value="_xclick">
<!-- Replace "business" value with your PayPal Email Address or your Merchant Account ID -->
<input type="hidden" name="business" value="your PayPal Email Address or your Merchant Account ID">
<input type="hidden" name="item_name" value="Online Payment">
<input type="hidden" name="item_number" value="OLP-00001">
<input type="hidden" name="no_shipping" value="1">
<input type="hidden" name="shipping" value="0.00">
<input type="hidden" name="tax" value="0.00">
<input type="hidden" name="button_subtype" value="services">
<input type="hidden" name="no_note" value="0">
<input type="hidden" name="country" value="US">
<input type="hidden" name="currency_code" value="USD">
<input type="hidden" name="lc" value="US">
<input type="hidden" name="bn" value="PP-BuyNowBF:btn_paynowCC_LG.gif:NonHosted">
</form>
<!-- END BUTTON EXAMPLES -->
<!-- END SAMPLE CODE SECTION -->
<br><br><br><br>
<hr align="left" width="50%" noshade>
<br><br>
NOTES:
<br>
In order to test the code, you must replace the "business" value variable with your PayPal Email Address or your Merchant Account ID.
</body>
</html>
