Laravel Nesting to 4 levels not working - laravel

Question

I have relationships like the following:
Category -> Subcategory -> Product -> Price
A Category contains X Subcategories.
A Subcategory contains X Products.
A Product contains X Prices (New Price, Old Price, One Record per Price Change)
I wanted to do the following:
#foreach($categories as $category)
[...]
#foreach($category->subcategories as $subcategory)
[...]
#foreach($subcategory->products as $product)
[...]
#foreach($product->prices as $price)
[... #endforeach x4 ...]
The 3 first levels are working. When using the 4th however ($product->prices) I get an Trying to get property of non-object error.
The relationships in the Models:
Category.php
class Category extends Model
{
public function subcategories()
{
return $this->hasMany('App\SubCategory');
}
}
SubCategory.php
class SubCategory extends Model
{
public function category()
{
return $this->belongsTo('App\Category');
}
public function products()
{
return $this->hasMany('App\Product');
}
}
Product.php
class Product extends Model
{
public function category()
{
return $this->belongsTo('App\Category');
}
public function subcategory()
{
return $this->belongsTo('App\SubCategory');
}
public function price()
{
return $this->hasMany('App\ProductPrice');
}
}
ProductPrice.php
class ProductPrice extends Model
{
public function product()
{
return $this->belongsTo('App\Product');
}
}
This is what I send to my View:
class PageController extends Controller
{
public function showMainPage()
{
$categories = Category::with('subcategories')->get();
$data = array(
"categories" => $categories,
);
return view('index')->with($data);
}
}
This worked fine, even with Products but began to have errors when using the ProductPrices.

Answer 1

As #GONG said, change your code for use eager load, this will run so much faster than use some foreaches.
See laravel docs: https://laravel.com/docs/5.3/eloquent-relationships#eager-loading