Michael

Add a paypal button (using shortcode) into your pages/posts 
Edit the wp-content/plugins/wp-paypal-shortcodes/wp-paypal-shortcodes.php for configure the plugin.
<h4>Shortcode</h4>
Add the following shortcodes to integrate PayPal into your pages / posts of wordpress.
<pre><code>[paypalBtn production="true" amount="55" item_name="ProduitB"]
</code></pre>
Insert the button in your pages or posts with this shortcode
<pre><code>[paypalBtn production="true" amount="55" item_name="ProduitB" business="seller@yourSite.com"]
</code></pre>
with the merchant email
<pre><code>[paypalBtn production="true" amount="55" item_name="t-shirt" optiontype0="select" on0="color" os0="red;green;blue;orange;yellow"]
</code></pre>
with option select
<ul>
<li>See the <a href="https://wordpress.org/extend/plugins/wp-paypal-shortcodes/changelog/" rel="ugc">Changelog</a> for what’s new.</li>
</ul>
<h3>Arbitrary section</h3>
Buy a product with a shortcode 
* @param production : choose if you are test phase, or production 
* @param amount : price for your product/service 
* @param currency_code : devise 
* @param shipping : shipping price 
* @param tax : tax price 
* @param return : url for the return (after buy) 
* @param cancel_return : url for the cancel (during the payment phase) 
* @param notify_url : url for the return (after payment validation IPN) 
* @param on0 : nom option 1 
* @param os0 : value option 1 
* @param on1 : nom option 2 
* @param os1 : value option 2 
* @param on2 : nom option 3 
* @param os2 : value option 3 
* @param on3 : nom option 4 
* @param os3 : value option 4 
* @param on4 : nom option 5 
* @param os4 : value option 5 
* @param business : email address of your paypal account 
* @param item_name : name of your product/service 
* @param no_note : autorized to file a note or not 
* @param lc : location 
* @param bn : button type 
* @param custom : custom field
<h4>Usage</h4>
[paypalBtn production=”false” amount=”55″ currency_code=”EUR” shipping=”0.00″ tax=”0.00″ on0=”optionD” os0=”ddd” on1=”optionE” os1=”eee” on2=”optionF” os2=”fff” business=”xxx@xxx.fr” item_name=”ProduitB” no_note=”0″ lc=”FR” bn=”PP-BuyNowBF” custom=”abc”]

WP Paypal Shortcodes

This plugin insert Paypal button (pages, posts).

CharlyLeetham

Easily embed a fully functional paypal buy now, subscribe or hosted button using shortcodes. Supports Wishlist Member and 
provides integration with iDev Affiliate and JRox JAM.
Copyright (C) Ask Charly Leetham (A Leetham Trust Project) 
This program is free software; you can redistribute it and/or 
modify it under the terms of the GNU General Public License 
as published by the Free Software Foundation; either version 2 
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, 
but WITHOUT ANY WARRANTY; without even the implied warranty of 
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
GNU General Public License for more details.
You should have received a copy of the GNU General Public License 
along with this program; if not, write to the Free Software 
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

WP Paypal Shortcodes vs Enhanced Paypal Shortcodes