Unfortunately, there is no way to get around the entry price for Bloxburg at this time, so there is no way to get in for free. Well, until the end of the beta period, at least, but there is no telling when that will finally happen. No matter what, you will need 25 Robux to play this game. Now, there is a chance that you could play it for free if someone gives you the Robux for it. For instance, Roblox will very rarely give everyone a handful of Robux due to an issue like a server shutdown and the like. Or you could ask someone like family and friends for Roblox gift cards for your birthday or another special occasion to get into the game.