Add a quote me / contact us form to my Wordpress website. We Hire event equipment.

Hi, I have no idea how much work this will entail or how much it should cost so please feel free to tell me how much is should be and how much work is involved. I am looking for a slick and simple and clear result so please bid accordingly. I hire event equipment. I need a add to quote button placed next to my products (see this page for an example) [login to view URL] This will then pop up a light box (not sure if I am using the correct terms here) and will add the product to a quote box, which should "float on all pages once activated??). The client can add more items, delete an item, change the quantity, click on the product to be taken to the relevant page and go to the "checkout" page which will ask for details such as event build days and address etc. Quite like a shopping basket would. Similar to this site. If you try it you can see it's quite an elegant solution. [login to view URL] Once clients had chosen the items and sent the form asking for a full quote then they would get an auto email that listed what they had asked for and tell them that we will be in touch, We would also get an email. The data for the forms would be stored online in some sort of DB. Hopefully within wordpress. But you could use any CRM or even mail chimp if it stores this kind of stuff. Notes:- We are running a WP site. [login to view URL] We don't want to change to any other platform. But would consider using another platform and using short codes to insert the products into the WP site. You can use any other plugins or widgets you think will help. Such as Gravity forms or whatever. I am happy to pay for these. I am very open to suggestions as to how this might work. It must be simple and clear for the potential clients. Over to you. Thanks for reading! Ask me any questions. I'm looking forwards to getting this working!