Answer for 300Mb internet?
Unfortunately, I’ve never had the pleasure of using a 300 Mbps connection. But based on some conversations with people around the country who do have 300 Mbps speeds available, it seems a good quality 802.11ac-based wireless router should be able to handle a 300 Mbps Internet connection. I would expect that you will spend around $150 or more for a router of this type. One example is the Linksys WRT1200AC AC1200. However, any router that is similar in specs should also work. You can spend upwards of $250 or $300 on current top-of-the-line wireless routers but it is questionable if you will see any benefit unless you have a significant number of devices on your network.
Whatever you end up buying, test it out and let us know how it works for you!