Hi Toussa, here is a website that rated vacuums:
www.health.com/health/gallery/0,,20516762,00.htmlThere are other organizations and websites that rate them, too, so search for something like: best HEPA vacuums. You'll be able to find a vacuum in your price range. Once you find one, make sure you pay attention to the model of the brand because not all models of vacuums work as well as others. Then, you can Google where you can buy the vacuum. Stores like Home Depot, Target, Walmart, etc. can even ship them to you or you can buy them online and pick them up at the store.
Good luck!