Hello sevarti! It's best to either buy it while they're in stock right now or when there's another kickstarter. They usually offer a bundle of all previous books, and this last one had a discount of like 5$ on the first book if you bought all three, so that's something! But it's approximately the same even in bundles, so you can either get all of them at once in the next kickstarter or buy all three now and get the fourth (last book for adventure 1 probably) when the kickstarter is out. (it'll probably help you save a bit on shipping if you get them all at once)
It's unclear if there'll be as much demand for all of adventure 2, what with everything going on in the fandom, but you can keep an eye out for that too.
Also, the comic will probably end (indefinitely) in a year or less because Minna's starting a new, quite different comic so you can look out for that!
