Usually they won't tell you the rate beforehand because they don't even know it. They know a rough budget and then it depends on your level of experience. Their budget info can be a range between (for Europe) e.g. 300-800 EUR/day. They will take a very senior guy for 800 EUR and they will take a less experienced guy for less. It all depends on your level, but they are unable to assess it themselves - the client does that, the recruiters don't have the necessary technical knowledge.
About chatting: Just be very direct and straight forward with them. Tell them exactly what's your situation and what you're looking for. You can only gain by this - they won't bother you with deals that aren't interesting to you. Don't over complicate it, I send them one-sentence answers if that's enough. If somebody stops replying or takes too long, just move on. There's plenty more. Similarly, if you take too long, they will just move on.