WP cli php script gives notice error: A non well formed numeric value

Question

My script gives this error: PHP Notice: A non well formed numeric value encountered. The offending line is:

// Calculate price with markup and round it.

$rounded_price = ( ceil ( ( $price * $multiplier ) / $nearest ) * $nearest ) - $minus;

Can you help me figure out how to fix the error notice?

--

Total script:

function round_price_with_limits( $price = null, $multiplier = 9.3, $nearest = 10, $minus = 0.05, $map = 0, $msrp = 9999999999) {
    
        // Ensure a price was provided.
        if ( !empty( $price ) ) {
    
            // Calculate price with markup and round it.
            $rounded_price = ( ceil ( ( $price * $multiplier ) / $nearest ) * $nearest ) - $minus; 
    
            // If price is less than minimum, return minimum.
            if($rounded_price < $map){
    
                return $map;
    
            }
            // If price is greater than maximum, return maximum.
            elseif($rounded_price > $msrp){
    
                return $msrp;
    
            } else {
    
                // Return price otherwise.
                return $rounded_price;
    
            }
    
        }
    }