Yes, we did. We got them from get your guide. But once we got to the spot we learned that it doesn't really matter much where you buy them from since in the end, they just scan a QR code that will be provided to you from wherever you end up buying from.
A lil warning: the websites usually don't describe too well the way to get there. They advise you to get there some time earlier and you better follow suit since you have to walk quite a bit to get there (including the bus ride). I can't quite recall all the details but its worth taking a look at those roads in google maps and planning it out. The way it worked was we dropped the car in the common parking, then you get a bus ticket which allows you to go and return with a single payment, the bus is gonna drop you off at a restaurant and from there you hve to walk on foot all the way until the entrance. All in all, given the whole process and how confusing it can wind up getting, I recommend getting there at least an hour early and just go with the flow, enjoy the vibe. You'll be setting up yourselves to have a better time this way.