Database for logging collaborative research or data

Ok, so I am developing a website to help door to door salesmen or direct marketers network and learn. Website is: happysolicitor.com
Here’s what I’m trying to do:
1. Allow any registered user to add to a database containing local municipal law regarding door to door sales.
2. Allow the database to be searchable and filterable based on a keyword, state, or field value

I keep trying to think of easy ways to do this. I’m familiar with php and coding but I do not want to risk the security or stability of the site because I hacked something together that wasn’t secure.
I thought: A Wiki would do it, but it’s TOO collaborative and it’s not easily viewable in a list and the content would not be 100% formatted the same.
I found a free plugin to create a form submission (Which is perfect) called Ninja forms but I don’t have an easy means of displaying the resulting submissions or giving “approval” to submitted forms.

The only plugin I found that will seem to give me the functionality I need is Gravity Forms but I have zero interest in paying $40 a year to list simple form submissions.

Any ideas would be fantastic. I’m open to using outsite code and or software to make this happen.

Thanks for your assistance,
Happy Soliciting!