After I bid my first proposal, I was selected by the customer to make a more complete proposal. Then he send me a complete description of the project he need to develop.
Such description was a bit complex and with the idiomatic barrier the things got a bit more complex.
Then, thinking in a way of show him my ideas with no place to doubts, Balsamiq Mockups came to my mind by first time to this sort of use (Not to design a real project, else to build a proposal).
Not being myself an expert on Balsamiq, else only a novice (I used it only one time before and for a few minutes) I clicked on the Balsamiq icon and, as usual on me, I started using without read nothing and trusting on the easy of adaptation of the product. And yes, it worked!.
In a few minutes I designed two mockups with not problems and showing exactly the things I wanted to show to the possible customer. I know the customer liked this way of show an early desing of the system because "A picture is worth a thousand words".
Balsamiq will be with me from now on for many tasks in my company.