My house construction is in progress in Whitefield. We are souring River sand from Hoskote Highway junction (Between Kadugode and highway toll gate) - you will find no. of trucks parked always. There you will find all variety of sand from AP & TN state. Be careful that you will be surrounded by 10s of people showcasing there sand and try to nab you towards their truck

As far red clay bricks, on way to chikkatirupati (via Hopeform signal -> channasandra road) you will find multiple table & wire brick moulding farms. If you have big requirement, I suggest go over there, have a look at different farms - get a samples and decide. I'm getting solid red clay bricks taken out from middle of kiln (flyash + coal oven) @ Rs. 5.55/-. The price is dependent of delivery location anyways.
Give me a PM if you need more info.
Cheers! Kartheek