Mohan (磨憨) is on the border between Laos and China. You can cross the border on foot.
On the Laos side the guards might come up with any number of reasons to squeeze an extra dollar or two out of you.
On the Chinese side there are many places to get a big feed for a small price. Then continue walking along the highway out of town, after which you'll soon get a ride to the first city, Mengla, from which you can continue on to Pu'er, Ning'er, and eventually the relaxing capital of Yunnan, Kunming.
You might consider heading to Jinghong, the main city of Xishuangbanna, which is an autonomous area for the Dai ethnic minority who are related to the Lao and Thai peoples.