Write to database from form in a plugin

Trying to create a simple products plugin just to experiment with plugins in wordpress. I have a plugin and here is the code for it.

<?php
/*
Plugin Name: Simple Products
Plugin URI:
Description: Keep a simple list of products.
Version: 0.1 alpha
Author: Chet Helms
Author URI:
*/

register_activation_hook(__FILE__,'simple_prod_install');

$simple_prod_version = "0.1";

function simple_prod_install () {
   global $wpdb;
   global $simple_prod_version;

   $table_name = $wpdb->prefix . "simple_prods_six";
   if($wpdb->get_var("show tables like '$table_name'") != $table_name) {

      $sql = "CREATE TABLE " . $table_name . " (
	  id mediumint(9) NOT NULL AUTO_INCREMENT,
	  time bigint(11) DEFAULT '0' NOT NULL,
	  name tinytext NOT NULL,
	  text text NOT NULL,
	  price VARCHAR(55) NOT NULL,
	  imgurl VARCHAR(55) NOT NULL,
	  UNIQUE KEY id (id)
	);";

      require_once(ABSPATH . 'wp-admin/includes/upgrade.php');
      dbDelta($sql);

      $welcome_name = "Product";
      $welcome_text = "description";
	  $welcome_price = "99.99";
	  $welcome_url = "https://site.com";

      $insert = "INSERT INTO " . $table_name .
            " (time, name, text, price, imgurl) " .
            "VALUES ('" . time() . "','" . $wpdb->escape($welcome_name) . "','" . $wpdb->escape($welcome_text) . "','" . $wpdb->escape($welcome_price) . "','" . $wpdb->escape($welcome_url) . "')";

      $results = $wpdb->query( $insert );

      add_option("simple_prod_version", $simple_prod_version);

   }
}

function simple_products_admin() {
    include('simple_products_admin_page.php');
}

function simple_products_admin_actions() {
	add_options_page("Simple Products ", "Simple Product", 1, "Simple Product", "simple_products_admin");
}  

add_action('admin_menu', 'simple_products_admin_actions');
?>

the page in the admin code is:

<div class="wrap">
<?php echo '<h2>Simple Products Admin</h2>'; ?>
<form name="product_form" action="<?php bloginfo('url'); ?>/wp-content/plugins/simple-products/process.php" method="post">
				<?php    echo '<h4>Add a Product</h4>'; ?>
				<p><?php _e("Product Name:" ); ?><input type="text" name="name" value="<?php #echo $dbhost; ?>" size="20"><?php #_e(" ex: localhost" ); ?></p>
				<p><?php _e("Price: " ); ?><input type="text" name="price" value="<?php #echo $dbname; ?>" size="20"><?php #_e(" ex: oscommerce_shop" ); ?></p>
				<p><?php _e("Image Url: " ); ?><input type="text" name="imgurl" value="<?php #echo $dbuser; ?>" size="20"><?php #_e(" ex: root" ); ?></p>
				<p><?php _e("Description: " ); ?><input type="text" name="text" value="<?php #echo $dbpwd; ?>" size="20"><?php #_e(" ex: secretpassword" ); ?></p>	

				<p class="submit">
				<input type="submit" name="Submit" value="Submit" />
				</p>
			</form>

</div>

process.php

global $wpdb;
$table_name = $wpdb->prefix . "simple_prods_six";

$name=$_POST['name'];
$price=$_POST['price'];
$text=$_POST['text'];
$imgurl=$_POST['imgurl'];

$insert = "INSERT INTO " . $table_name .
            " (name, text, price, imgurl) " .
            "VALUES ('$name','$text','$price','$imgurl')";
$results = $wpdb->query( $insert );

print "Your information has been successfully added to the database.";

and the process form which doesn’t work or carry over the global. Any ideas? What am I doing wrong? Thanks.