The PCs in my game as thinking about going through a gate, but are wary of doing so without throwing some Gate spells to find out what's going on on the other side.
Here is what I said about Gate spell scrolls:
"a Scry Gate scroll is Special Order (1d+1 weeks, I'll do it from the time I have a request* on record) and will cost 4x as much - $200 per point = $800 per scroll for an unpowered one. Why so much? Gate spells are rare, and the few wizards that know them know you'll pay what they ask."
Since the party has a lot of broke or nearly broke PCs, this might mean exploring a gate (which I'd personally like them to do) might get back-burner'ed until people have more disposable income. But that's how it goes - it's pretty lame to make a difficult spell for a rare and potentially lucrative source of adventure cheap and easy. If the PCs really want to, they can learn the spell. That'll be costly (4x as much as well) but it's easily done.
* Editing later: And payment.