无法使用laravel添加请求中的数据

I have this function:

public function store(Requests\OfferRequest $request)
    {

            $offer = new Offer($request->all());

            Auth::user()->offer()->save($offer);

            $maxoffer =  Maxoffer::where('article_id', $request->input('article_id'))
                        ->where('start', $request->input('start'))->get();

   if($maxoffer == null)
    {
      Auth::user()->maxoffer()->create($request->all());
    }
    else
    {
      if($maxoffer->price < $request->input('price'))
      {
        $newOffer = Auth::user()->maxoffer()
                    ->where('id', $maxoffer->id)
                    ->update(['price'=>$request->input('price')]);
      }
    }

        Alert::success('Offer is succesfully added!', 'Good job!')->persistent("Close");

        return Redirect::back();

    }

but I can't add data because I got this:

ErrorException in OffersController.php line 63: Undefined property: Illuminate\Database\Eloquent\Collection::$price in OffersController.php line 63 at HandleExceptions->handleError('8', 'Undefined property: Illuminate\Database\Eloquent\Collection::$price', 'C:\wamp\www\bidbook\app\Http\Controllers\OffersController.php', '63', array('request' => object(OfferRequest), 'offer' => object(Offer), 'maxoffer' => object(Collection))) in OffersController.php line 63

What is the problem here?

Try this

 $maxoffer =  Maxoffer::where('article_id', $request->['article_id'])
                    ->where('start', $request->['start'])->get();

The following returns a collection:

$maxoffer =  Maxoffer::where('article_id', $request->input('article_id'))
                    ->where('start', $request->input('start'))
                    ->get(); // Returns a collection

So you get the error. Just change the get to first for example:

$maxoffer =  Maxoffer::where('article_id', $request->input('article_id'))
                    ->where('start', $request->input('start'))
                    ->first(); // Returns a single Eloquent Object

Now, this will return a single Eloquent Model object and will work if any model was found.