How not to set price for some products and instead have an enquiry option?

Yes, it is possible to set just an enquiry form instead of setting a price for a product. You may want customers to enquire about a product for various reasons without disclosing the price. This is possible through CloudShoppy.

You can have this enabled by purchasing an Order Quantity app.

Under ‘Product catalog -> Products -> Inventory & Variants’, click edit and you have option to set the inventory policy.