I've recently acquired Invasion and was wondering about a couple of things about developments and quests.

1. Are developments free, since they are played face-down?

2. Can a development be turned face-up by paying its cost, or is it permanently face-down?

3. Are Quest cards discarded after completion?

This sounds really basic, but there are no references to costs or restrictions on developments or explicit details on how quests work in the basic book. Maybe I need to have a closer look.

1. Yes, the only limitation is that you can play one per turn.

2. Permanently face-down unless you have a card that allows turning it face-up (Rip Dere 'Eads Off!)

Many thanks. Just patching up the holes that the rulebook has given