Yes, but you need to customize or manually generate your item button code. The online button creator has it's limitations. You can create code that allows the donor to choose their own amount however, this works like a subscription. The donor decides what montly amount to donate, unfortunally they cannot change the amount from month to month.
For example, check out the code below for some ideas:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Button Example Code</title>
<!-- START META TAG SECTION -->
<meta charset="utf-8">
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
<meta http-equiv="Content-Language" content="en">
<!-- END META TAG SECTION -->
</head>
<body>
<!-- START SAMPLE CODE SECTION -->
<!-- PARAGRAPH 1 -->
Donation Examples
<br><br>
Make a One Time Donation or setup a Donation Schedule like a Subscription.
<br><br>
<!-- Start of Form -->
<form target="_self" action="https://www.paypal.com/cgi-bin/webscr" method="post">
<!-- If using a Business or Company Logo Graphic, include the "cpp_header_image" variable. -->
<input type="hidden" name="cpp_header_image" value="https://yourwebsite.com/logo.jpg">
<input type="hidden" name="cmd" value="_xclick-subscriptions">
<!-- <input type="hidden" name="redirect_cmd" value="_xclick-subscriptions"> -->
<!-- Replace "business" value with your PayPal Email Address or your Merchant Account ID -->
<input type="hidden" name="business" value="your email address">
<input type="hidden" name="item_name" value="Widget Fund Donation">
<input type="hidden" name="item_number" value="WFD-1002">
<input type="hidden" name="no_note" value="1">
<!-- no_shipping value 2 needed to send the free gift -->
<input type="hidden" name="no_shipping" value="2">
<input type="hidden" name="tax" value="0">
<input type="hidden" name="lc" value="US">
<input type="hidden" name="currency_code" value="USD">
<input type="hidden" name="button_subtype" value="products">
<input type="hidden" name="no_note" value="0">
<input type="hidden" name="cn" value="Add special instructions to the seller:">
<input type="hidden" name="bn" value="PP-BuyNowBF:btn_buynow_LG.gif:NonHosted">
<!-- Replace value with the web page you want the customer to return to after a successful transaction -->
<input type="hidden" name="return" value="http://www.yourwebsite.com/ThankYou.html">
<!-- Replace value with the web page you want the customer to return to after item cancellation -->
<input type="hidden" name="cancel_return" value="http://www.yourwebsite.com/Cancel.html">
<!-- -->
Enter the amount you would like to donate:
<!-- a3, Required, Regular Subscription Price -->
<input type="text" name="a3" size="4" maxlength="7">
<br><br>
<!-- src, Optional, Recurring Payments, 0 no recur, 1 payments recur -->
<input type="hidden" name="src" value="1">
<!-- -->
Select the length of the desired Billing Cycle:
<!-- p3, Required, Duration based on the value of t3 -->
<select name="p3">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="15">15</option>
<option value="30">30</option>
</select>
<br><br>
<!-- -->
Select how often you would like to Donate:
<!-- t3, Required, Subscription Units D W M Y, -->
<select name="t3">
<option value="D">Day(s)</option>
<option value="W">Week(s)</option>
<option value="M">Month(s)</option>
<option value="Y">Year(s)</option>
</select>
<br><br>
<!-- -->
Select the number of Donation Payments you would like to make:
<br><br>
<!-- srt, Optional, Recurring Times, must be used with src -->
<select name="srt">
<option value="">Until Canceled</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="6">6</option>
<option value="12">12</option>
<option value="18">18</option>
<option value="24">24</option>
<option value="36">36</option>
</select>
<!-- sra, Optional, Reattempt on failure 2 more time, value 0 or 1, if 0 no reattempt -->
<input type="hidden" name="sra" value="1">
<br><br><br>
Thank you for your Donation,
<br><br>
Please Select your Free Gift:
<input type="hidden" name="on0" value="Free Gift Choice">
<select name="os0">
<option value="Solar Calculator">Solar Calculator</option>
<option value="Key Chain Light">Key Chain Light</option>
</select>
<br><br><br>
<!-- -->
<input type="hidden" name="bn" value="PP-SubscriptionsBF:btn_donateCC_LG.gif:NonHosted">
<input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_donateCC_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
<img alt="" border="0" src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" width="1" height="1">
</form>
<!-- End of Form -->
<!-- END BUTTON EXAMPLES -->
<!-- END SAMPLE CODE SECTION -->
<br><br>
<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>
