Php codeing and database

i need some simple php work

im finsihing my bootstrap site http://vpylypenko.com/dev/manchesterturffarm/

i need it to work so that customer inputs amount of turf in the box e.g 10, 15, 20 etc and they get a price

they will then get the option to add bags of topsoil , these will have a set price of 40 a bag, so if theys elect 3 it adds £120, 4 adds £160 etc etc the soil cost is automatically added on to the turf costto the turf cost

customer is then shown a total order cost, they can then click a button called Order and a pop up form will appear and they can send us the over in a message, THIS IS NOT ECCOM it is just a simple submit form with address and then we call them to arrange

I will need a simple cms database so i can easily change prices of turf and soil if required

i will provide a spread sheet with the turf prices from 10 to 200