[Undefined Index Error]

I realize this is a very common issue and it stems from at least the way I understand it, the code not checking if something is declared before declaring it. That begin said I tried adding isset code to some sections where I was getting errors and they are still errors there so Im totally lost. I am very new to php so if this is a stupid question please treat me like a 5 year old if you would and help me understand my errors

 

The errors are as follows:

 

 

Notice: Undefined index: key in /home/mdfehr/public_html/store/catalog/controller/common/cart.php on line 103Notice: Undefined index: recurring in/home/mdfehr/public_html/store/catalog/controller/common/cart.php on line 108

 

And the Code it pertains to(starts at line 103): 

			$data['products'][] = array(
				'key'       => $product['key'],
				'thumb'     => $image,
				'name'      => $product['name'],
				'model'     => $product['model'],
				'option'    => $option_data,
				'recurring' => ($product['recurring'] ? $product['recurring']['name'] : ''),
				'quantity'  => $product['quantity'],
				'price'     => $price,
				'total'     => $total,
				'href'      => $this->url->link('product/product', 'product_id=' . $product['product_id'])
			);
		}

Any suggestions are appreciated.