You need to provide more information to make any sort of an estimate even a half-assed guess. I'm not trying to be rude, please take my critique as a bit of humour and a bit of tough love.
It would center around user-generated textual content and include features like ratings, searches with filters, and a dynamic hierarchy of categories and subcategories.
You've told us absolutely NOTHING about what you'd like to be able to do with the website. That is actually a broad description of about half of the internet. What do you want to DO with your site? If I'm a user of your site what can I DO on it? What features are you going to offer that is going to make me want to sign up? How do you intend to generate revenue off of the idea?
I don't anticipate doing anything too fancy in terms of design.
That is not a project requirement, instead that is why you want a technical person to work with you and use their expertise to turn your vision into a functional website.
"User-generated textual content" could be anything from a personals site to a recipie competition. One requires extra consideration to keep perverts and wierdos out, the other requires understanding that your users are Oma's and Hausfrau's who need extra guidance.
'Searches with filters', by definition a search is a filter. Anyone making you a website without some way for at least administrators to search through their content should turn in their license and go back to Geocities.
'Dynamic hierarchy of categories and subcategories'. ... I'll leave this one as an exercise for the reader.
It's hard to share your ideas with the world, but if you want a qualified guess as to what this might cost you so that you don't get reamed when you get a real estimate in private then you're going to have to open up a little and describe things better.
Right now the only advice you should listen to is that anyone giving you an estimate with that little to go on is lying and trying to steal from you.