Hi Lili and welcome
In my experience these are the tyrekickers hoping to get a look at or hang about with a prossie for free, and I doubt he's expecting to pay much if at all (he probably thinks you'll be falling over yourself with gratitude if he offers to cough up for a midrange lunch somewhere
) somyou'll need to be clear from the outset.
I would get a deposit for any costs which you won't be able to get back, like travel and this also ought to tell you more as I suspect you won't hear from him again once you've asked. As to the booking, if he's expecting to see you in a public place then some people would charge a lower rate but not all - as you said, your time is money so if you want your full rate, get it.
Wanting regular clients doesn't mean you have to drop your boundaries and entertain every chancing twat who contacts you. Genuine punters don't need to 'discuss ideas' in a separate encounter because they have other things to do - they just book, turn up and pay without any of the messing about and that's what you want in a regular
.