I would not go with Wordpress

The disadvantage of Wordpress is that it is basically a blogging software, turned into a website software, turned into an e-commerce software, turned into everything. The point is lots of workarounds, safety issues, plugins needed that might not work with one another etc. Plus you must be able to maintain the server/ hosting environment. Just because it "runs'' as it does with a shared hosting (worst option for business purposes) does not mean it is properly configured for safety or speed.

In my opinion the best tool for your idea is Bubble.io
You can start free and only pay when you go into production mode.

A few big advantages of Bubble (especially in regards to your idea) are:

*in-built sign up/ sign in /forgot password functionality (can be implemented in 10 minutes with few clicks)

*in-built database, easy to create necessary database structure

*automate basically everything with an "If this / then that"- editor

*dynamically insert content from database

*you own your customer's data and can export it

*marketplace of free and paid plugins

* payment processing via 3rd party provider

Of course no software is perfect so here some of the disadvantages to consider:

* there is a learning curve, especially when it goes beyond the basics

* the UI editor is outdated, as it works with absolute positioning coordinates and width/height instead of relative value for easy responsive design. There is a responsive module but it is not intuitive and a pain to debug

* the application will be slow with lots of users

* while it is easy to build so it works it is hard for non-coders to build processes that do not slow down the software, as it all depends on how you write and read data.

Overall if you do not have the budget and just need to start out I would definitely say the pros outweigh the cons. As you can build a MVP in a reasonable timeframe, get started, build your community and deliver a proof of concept to get the necessary funding.

If you need any help with that let us chat:

https://clarity.fm/gerdtf