Considering the standings requirement drop for setting towers in Empire Space, it is of no surprise that high sec moons are almost nearly full with offline POSes. Doing some forum surfing today, I came across this post "That Didn't Take Long.. Highsec Filled with Offline POSes."
If you ever thought you might want a POS, your window of opportunity is quickly coming to a close. Everyone and their uncle has probably scarfed up all the moons in your area. IF you are considering a POS (ever), get out there and scout some moons. You might still find one.
The good news is that the majority of people appear to have thrown up only small POS spikes, so if you really want, you could war dec them and tear them down. If you prefer the diplomatic approach, I suppose you could offer to buy the moon. I always worry about transactions that can't be backed by CCP (such as contracts for goods). It very easy to be scammed on such a transaction. Be mindful and as always, fly safe-ish.