Badaling Great Wall was rebuilt after the establishment of the PRC, therefore, it kind of lacks the natural tasts. Also, it is usually crowded. I strongly recommend the cruise from Jinshanling to Simatai, in which you can take a walk on a 10 kilometer original Great Wall. The whole trip takes 1 day and costs like $10.(Traffic fees not included)I tried it. It's pretty good! If you need further information, please mail yahoo.com.cn|flanker1118, I'll be glad to help.
May your stay in China happay and comfortable.

Generally, dinning in Beijing is not so expensive. Beijing has a lot of restaurants which meets consumers' different needs. Roast duck is strongly recommended. The most famous roast duck restaurant is Quanjude, which has a lot of branch stores all over beijing. However, you can always order a roast duck in most medium-sized restaurants in beijing. The cost is around $4-20 per duck depends on different stores. One order can serve 2-4 people, of course you should order other food.
For further information, you can contact yahoo.com.cn|flanker1118

Accommodation in Beijing may be tough for you if you want to save money and stay comfortable. One tip is that you may try hotels in universities. You can always get a cheap room, which is also clean and tidy. It costs like $5-20 per room per day. And if you are lucky, you can get a college student as your tour guide, which makes your travel more convenient and eliminates unnecessary troubles. For further information, you can email yahoo.com.cn|flanker1118.
May your stay in Beijing happy and comfortable.