Find beta testers

Hello,
I would like to find some beta testers for my website www.boostmybrain.net
The website has just been created and I would like to get critics from beta tester to help us improve it.
The goal is that the website matches the users' need.
Idealy 200 beta testers would be good. These beta tester should be interested by the website and willing to take the time to review it, use it. They would be the first community of the website.

About the website: the goal is to challenge the cognitive fields of the users, such as memory, speed, logic, flexibility, attention. There are 20 games, a training program, and plenty of advices for some self-development.
There is a free mode (4 free games/day, a free training program) and some monthly/yearly plans to get full access.

So it would be best to target people with interest in self-development, challenging their brains, playing games...

To help we'll give 6 months free full membership for the beta testers.
The website is available on computer and tablets but not on smartphones for now.

Please indicate how you plan to find the beta testers, the time needed and your budget.