Digital Signage Portal

Hi, I'm going to enter the business of digital signage. I do not have much budget, so I want a field that allows me to start with a good basic idea and then developing other solutions.
I already work in the field of visual communication for architectural design and real estate, so I know already many stakeholders.
The idea is to be proposed to all real estate in the area and shopping centers with greater influx of people.
Create software for touch screen that allows the potential candidates to search for a property, filtering by price, geographic area (Google maps), type of home, rental, sales and so on. The system responds with ads of real estate agencies that decide to publish in my system. The user can send via bluetooth, email, SMS, the details of the offer, or fill out a request form.

Doing so would, as already happens for reviews of real estate ads paper, a variable but steady income weekly or monthly. Then you could pay more, perhaps, to stay on the homepage of the touch screen when no one is using, etc..

In your opinion is a good solution? The costs will be related to: software (my brother is a programmer), display, rental of commercial space where to install everything. There are other costs?
What technology and what size display would be appropriate?
Suggestions?

thanks

Hello,
we got the total solution you have,
Please let us know which country you are going to deploy and how many units and what budget you are targeting to .

stevent@cyber-sys.com.hk

regards