Amazon Product Advertising API. How to get the lowest price for the seller which is not Amazon?

Question

I'd like to get two prices for an ASIN using the Amazon Product Advertising API. One price is for the product sold by Amazon and the other - the lowest price for the product sold by a 3rd party (much like it's done on camelcamelcamel).

I use OfferFull response group and check the Merchant.Name field in the response to see if the product is sold by Amazon or not.

So if it's not, then I got the cheapest price for a 3rd party seller in the Offer, and all I left to do is to issue another request with a parameter MerchantId=Amazon to get only Amazon deals. But what if the Amazon has the best offer? Is there a way to figure out what is the lowest price for 3rd party sellers then?

Answer 1

Put in your RESPONSE GROUP "Offers" and in optionalParameters set MerchantId to "All"

Example:

$response = $this->amazon->responseGroup("Medium,Offers")->optionalParameters(['MerchantId'=>'All'])->lookup($amazon_asin);

And them

if(isset($item->Offers->Offer->OfferListing->Price->CurrencyCode)){
    $amazon_data_price = $item->Offers->Offer->OfferListing->Price;
}elseif(isset( $item->OfferSummary->LowestNewPrice->CurrencyCode )){
    $amazon_data_price = $item->OfferSummary->LowestNewPrice;
}elseif(isset($item->ItemAttributes->ListPrice->CurrencyCode)){
    $amazon_data_price = $item->ItemAttributes->ListPrice;
}elseif(isset($item->Offers->Offer->OfferListing->SalePrice->CurrencyCode)){
    $amazon_data_price = $item->Offers->Offer->OfferListing->SalePrice;
}