$biddingStrategyConfiguration = new BiddingStrategyConfiguration();
$biddingStrategyConfiguration->setBiddingStrategyType(
BiddingStrategyType::TARGET_SPEND
);
// You can optionally provide a bidding scheme in place of the type.
$biddingScheme = new TargetSpendBiddingScheme();
$biddingScheme->setBidCeiling($_GET['cpc'] * 1000000);
$biddingScheme->setSpendTarget($_GET['cpc'] * 1000000);
$bid = new CpcBid();
$money = new Money();
$money->setMicroAmount($_GET['cpc'] * 1000000);
$bid->setBid($money);
$biddingStrategyConfiguration = new BiddingStrategyConfiguration();
$biddingStrategyConfiguration->setBids([$bid]);
$biddingStrategyConfiguration->setBiddingScheme($biddingScheme);
$campaign->setBiddingStrategyConfiguration($biddingStrategyConfiguration);
but this now throws an error
PHP Fatal error: Uncaught Google\\AdsApi\\AdWords\\v201809\\cm\\ApiException: [OperationAccessDenied.OPERATION_NOT_PERMITTED_FOR_CAMPAIGN_TYPE @ operations[0].operand.biddingStrategyConfiguration.bids; trigger:'SEARCH']