simple shop website 35$

Hello, i have a small project and I need a simple shop system it's not complicated at all, the website style is already done, so it's an inventory system and shop system for inventory, we will use [login to view URL] so we can low the budget, but there is a small change on the GitHub project it's so simple the pic will explain it [login to view URL] the drop box (CATEGORY) I can add what is that code so if the item is a personal computer it's put (pc) before the item code and for the code generator up to the developer you can use API for that [login to view URL]:4/complexity:numeric it's only 4num code that's it for the inventory manager for the user shop I want a way so I can make stoke available show to the client [login to view URL] out of stoke low availability under 5 stoke medium availability under 35 high availability more than 35 [login to view URL] and for the checkout, the website has a calculator for cart but I want you to make a coupon and it gives a discount with an amount of money or % and sipping option so every option have a separate fee, when he goes for the placing order there is no login for the client, it's only got his information and makes invoice with invoice code and redirect the client to a page opens in a new tab on his browser so he can save the invoice code -and he can see the order status -and payment option -and the transaction code (after completing the payment) -shipping option -sipping track code and all of that it's updates manually by the admin in inventory page and the client gets an email that we will contact him soon and the admin email get a notification that there is a new order sorry for the long description but i want everything clear and remember im in low budget bids more then 40$ save me some time and don't bid further information and website style will be given after regards