I am currently weeks apart from releasing my pet project, which I am working on for almost 6 years now. Of course, there were a few stops here and there, but overall I've spent a lot of time and effort on this to make it work. It is far from complete but I am really happy with the results.

Now, since I am not a professional by any means - it is all a hobby for me - I was wondering, that how much my work would cost, if it were to made by professionals. Below the details so you can get a grasp of the thing.

The whole system is for our family business. We are selling parts for an old-timer truck model. The website was pretty much done already, people like it, it only needed some polishing and adding of the new features. But the thing behind it is monstrous (at least for me).
Apart from the custom-made CMS for the website (most of it was done already and didn't need to change), we can handle orders, partners, prices, stocks, overdue partners, pretty much anything a CRM would do.
There is a logic to automatically make orders based on import prices, or give the customer a custom discount based on the price gap of each product. There are products, which can contain other products, and their prices are dynamically changed based on a given formula, once an underlying product price changes. We can send e-mails when an order status changes, and there is also a page, where a user can interact whit their order, like changing the shipping or the delivery address. The system is (or will in the following weeks) also connected to multiple shipping companies' API, so we can order deliveries and print labels directly from our system. The whole thing is a custom made Laravel project by the way. There are countless more features, but I've just spent 2 hours explaining all to my father and was only be able to cover like half of it.

And why it is all custom made, you ask? Well, the business logic is a bit twisted, so it would be hard to operate as a regular web shop, since the availability of the products are uncertain, given the fact that it is a model, which isn't manufactured in 30 years. So, we can't just accept and send orders without confirming. It is also a thing, that people usually don't know what they need to order for their truck, so we have to help them, so they don't waste their money and the precious last pieces of a part unnecessarily.

Sorry for this rather long post, and it might feel like I just want to brag (well, I kinda do), but I am honestly interested in what such a custom product would cost in the market.

Thank you for your time answering.