The vast majority of the indigenous peoples living in Mondulkiri are subsistence farmers, who are planting some rice and other vegetables, more or less to feet themselves. There is also a quite common production of the famous rice wine here, which is one of the best in the country. Additionally the indigenous people are selling handmade products such as bracelets, necklaces, scarfs, Kramas etc. to the few visiting tourists.
Mondulkiri has a quite big influence from Vietnam, which shows you the marked in Sen Monorom. Lots of Vietnamese products are sold here.
Unfortunately in the past 2 years the selling of real estate became a big source of income due to the fact, that international mining companies are buying land to find bauxite (a very valuable mineral). The worst are instances of dispossession of indigenous lands, which are occurring in some parts of the province and also in the adjacent province of Ratanakiri.
Anyhow Mondulkiri is so sparsely populated that the provincial capital does not have an adequate market compete to other provinces of Cambodia. But fertile red soil, water sources, wild animals and quality hardwoods abound and the weather and scenery are perennial assets.