How should I handle the sale of my two remaining slots?

Hi All

I am a marketing and PR consultant. I've been taking bookings to do some press-releated work for a number of companies attending a conference.

So far I've sold four of the six slots I have available. For the four sold, none of them queried my price (which made me think that my price was too low!).
I'm now wondering how I should handle the sale of my two remaining slots.

My normal method is to meet potential clients, then send over a detailed proposal with pricing.

However, I'm starting to wonder if I should ask instead what their budget is (which is something I normally avoid), or use another pricing method.

I'm also thinking of updating my website to say I now have only two slots remaining, and that I'm likely to be booked up for conference projects soon to move things along in terms of the time between initial enquiry>signing contract. I don't have any pricing info on my website at the moment, as in the past I worried that it may put off potential customers with lower budgets.

What would you do if you were in my situation?

Many thanks, Warhola.