Forgot to close output buffer

You can fix that by adding return ob_get_clean(); as the last line in the function pricing_function() in pricingtable.php

Use the plugin editor. On the first file that comes up (should be pricingtable.php), search for the line function pricing_function. Use the browser search (Control + F), will bee much faster. return ob_get_clean(); is added at the very end of that function.

This is what it’s likely to be:

// Plugin code
<div style="clear:both"></div>
    </section>

<?php
    return ob_get_clean(); // <======= HERE IS WHERE YOU PLACE THE LINE
}
class easy_pricing_table_widget extends WP_Widget{
//...more plugin code

I hope this helps.