abantecart

Enable eCommerce in your WordPress site. Embed the “buy now” products and categories from your AbanteCart store. Requires no coding. Just add the plugin and paste the embed link to the blog post or page.
<h3>What is AbanteCart?</h3>
AbanteCart is a free feature-rich shopping cart application, right out of the box. Standard features allow you to set up a complete eCommerce site with all the tools needed to sell products online.
<h3>See AbanteCart In Action</h3>
<ul>
<li><a href="https://www.abantecart.com/shopping-cart-demo" title="AbanteCart demo" rel="nofollow ugc">Demo Store</a></li>
</ul>

AbanteCart Embed

You can now enable eCommerce features in your WordPress pages.

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.

AbanteCart Embed vs Enhanced Paypal Shortcodes