How old are they? How many roos/hens? How much are they asking? I would be asking these kinds of questions but.....I'd probably be inclined to say "go for it". I'd love to have some Javas (planning to get some when possible). If you already have other chickens, you will also need to have a separate area for the new flock to be in quarantine for the first 30 days. And you'd also need to read up a little bit about integration once the quarantine period is over. If you don't already have chickens, you won't even have those kinds of concerns.