Ads are not likely the best place to be finding clients. I tried this with our consultancy a few times and they never seem to pay off, even when we did it on linkedin. Although at least with linkedin, we did connect to people and it helped expand our network.
Almost all of our clients come from networking and meeting people. You have to put yourself out there. Then from there you will also get referrals etc. Getting sales is still personal, especially if you are asking for $10k+, people want to feel they know you a little or know someone that knows you.
As for your pricing, if it were me, I'd likely put it as "starting at" and pick a reasonable number (gives you flexibility too). Or give general guidelines, like "typical 3 page website developed in approximately 2-3 weeks $xxxxx." Or whatever the real facts you feel are. But that way it is less a rigid structure and more a guide for people that are interested. Giving examples like this I think doesn't scare people, but when they see 1-3 pages $25k for a mobile app, they aren't sure what that means but it seems expensive. Remember, the first thing someone does is take whatever numeric metric you put on your price and divide it into your price, so in this case they would say each screen is costing them $8,333, which will scare them. This is just human nature.
For example, we price per week (or per day for small things), and the first thing everyone does is divide our rate into 40 hours or 8 hours for the day. But for us our weekly hours commitment is 30hrs per developer to a client so that the developers have time to accomplish all those other tasks that come up and meetings etc. So it isn't X/40, its really X/30, but it doesn't even matter to us because we will never bill that way, but it is still the thing every client does in their head and I still wind up answering from time to time.
My only point about pricing then is to be careful putting numeric metrics near a price where it might make your price seem high, when in reality there are 100 other things that go into making that price. Hopefully that makes sense. Additionally, I see the starting at pricing usually lets people feel like they can negotiate and get a custom deal versus having to pay a fixed price and maybe not get what they truly want.