get single column value in laravel eloquent

$collection = collect([
    ['product_id' => 'prod-100', 'name' => 'Desk'],
    ['product_id' => 'prod-200', 'name' => 'Chair'],
]);

$plucked = $collection->pluck('name');

$plucked->all();

// ['Desk', 'Chair']

Vehicle::find(3)->value('register_number');

$items = DB::table('items')
             ->select('id', 'ref_code', 'name', 'price')
             ->where('ref_code','=', $request->ref_code)
             ->first();