deal of the day homepage

Is it possible to modify the design of the web-page to look similar to groupon ( ?

Very much so.

how much will it cost me. i am trying to edit the dsign.css file but iy will take me a lot of time since i do not have experience with this sort of tasks.

At this point it is hard for me to say exactly what you are trying to accomplish to give a quote. You may privately PM me or reply here with a description of your vision.