Salaam, we can provide you with a full flash website in lower cost than you mentioned due to the nature of your work (Islamic Charity).
We offer you a 1 month free maintenance contract which means you can request as many changes within that month!
As for the sample, we can provide you with a fully interactive flash presentation of our trading software. We can also provide mock-ups to test our skills and abilities.
We are mainly interested in your project due to its noble nature:)