If you're vlogging the BEST thing to do is get a shotgun mic, with a boom pole rig. But that would be more for a permanent studio setup, where you don't want your microphone seen on camera. But that would probably triple your budget.
The best option IN your preferred price would be a blue snowball. I have one and it sounds great. The drawback is that it has to be set more on a table and has to be moderately close to get quality sound (About no more than two feet away from where you're speaking). It's probably more preferred to gamers, since they don't have to worry about being seen hunkered down over their microphone. But you could definitely make it work.
Then, as you said, you can use your camera's mic. It's free, but I don't recommend it. It's been proven that it is easier to irritate your sense of hearing than your sense of sight. (Which is why no matter what videos you're going about making, worry about decent sound or sound recording hardware before a 500 $/£ camera lens.)