[Manyasha]

INSIDER73,
Здравствуйте, так пойдет?

<script>
window.addEventListener("load", function() {
	[].forEach.call(document.querySelectorAll(".products-view-block-custom"), function(e){
		if (e.querySelector(".price .price-unknown")){
			e.querySelector(".block_payment_custom-cc").style.display = "none";
		}
	});
})
</script>
<div class="products-view-block-custom">
    <div class="block">
        <div class="price">
            <div class="price-current cs-t-1">
                <div class="price-number"> 20 000</div>
                <div class="price-currency"> руб.</div>
            </div>
        </div>
    </div>
    <div class="block_payment_custom-cc">
            <a href="">заказ</a>
    </div>
</div>
 
<div class="products-view-block-custom">
    <div class="block">
        <div class="price">
            <div class="price-current cs-t-1">
                <div class="price-number"> 20 000</div>
                <div class="price-currency"> руб.</div>
            </div>
        </div>
    </div>
    <div class="block_payment_custom-cc">
            <a href="">заказ</a>
    </div>
</div>
 
<div class="products-view-block-custom">
    <div class="block">
        <div class="price">
             <div class="price-unknown">Свяжитесь с нами насчет цены</div>
        </div>
    </div>
    <div class="block_payment_custom-cc">
            <a href="">заказ</a>
    </div>
</div>