Yes the cost for food and transportation can vary depending on how your appetite is and what you like to do. If your staying in guangzhou at least try to get a decent room at least a 4 star if you can afford 5 star go with that. The price about a week again will vary depending on your lifestyle could be as less as 300 kuai to up to 1000 kuai.

Classical mattaya answer, lots of words and no substance.  But he got his 4 points, which is what he is after do.

Lets help this gentleman.  When I am in Guangzhou, I always stay at the Nanfeng Hotel.  It is 4 stars, but in China star rating means price level, not quality of service, so pay no attention to that.  To make reservations, I always use Agoda Travel Services, fast, cheaper than direct (most of time 20 % discount) for advance reservations.  There, you will find a nice hotel, very nice rooms, excellent service.  Only drawback is way out of city center, but taxis in China are cheap, ride from downtown is always 40 to 45 Rmb (less than $ 8 bucks).  If made thru Agoda, use Rembembi as currency, not dollars, even cheaper, between 288 and 400 Rmb per night depending on date.  Restaurant is nice, excellent service, good food and also well priced.  At hotel, one of Asst Mgrs is Christy, speaks excellent English, very nice and helpful Lady, tell her on special message while doing reservations with Agoda that her "father from Nanning referred you", and she will insure you get a nicer room at same price.  Other employees do speak some English, not much, but Christy will guide and help you plan your day.  Breakfast buffet is included in room price, good until 10 am.  From airport to hotel ride is about 100 Rmb, be aware, some taxis will quote from 150 to 250, do not accept that.
There are some good restaurants near hotel too, dinner there is around 70 Rmb per person, but if you do not speak Mandarin, it will be hard for you to order food.  Take card from hotel, show it to taxi drivers so they know where to take you.  Hotel name is pronounced "Nanfong", but written Nanfeng.

Good trip to you

The best place to find a nice, clean, reasonable hotel in Guangzhou, IMHO, is to use www.elong.net.  It's one of the largest travel agencies in China, if not the latest, and they will offer you many, many choices for Guangzhou.

You may wish to consider an apartment hotel through them.  I have used it before and it was a quite nicely furnished two bedroom furnished apartment, quite large, in a quite neighborhood and the price was really not expensive.

As for food in Guangzou, it's not an expensive food-wise and you should have no trouble surviving on a decent budget.  Avoid the big Western name restaurants in Tian He and you will be alright.

And take the subway as much as you can.  It's fast, expensive, reliable and you won't be cheated.