Hi,
I have 14+ yrs. experience of osCommerce/opencart/zencart/wordpress/woocommerce/prestashop/Cre Loaded. I have already worked on hundreds of ecommerce websites including template integration, module installation and custom module development. I have contributed 3 payment modules (eway, netbilling and ccavenue) to oscommerce community and developed many custom payment, shipping, reports and other modules for my clients. Please also visit the following link to see reviews for my experience and customers satisfaction.
http://www.freelancer.com/users/feedback_138265.html
Please note that due to functionality we can not make price field to except text value. however to achieve the functionality, I can add 2 radio button (only 1 can be selected at a time) on product add/edit page in admin to display "Price on Request" on "To be Confirmed" instead of price on the site. I also understand that if a product is set to any of the 2 conditions, then that product can not be added to cart. so we also need to hide add to cart button for such products.
Thanks
Kavita