Answer :
Two of the major economic incentives that were given to draw settlers to the West were 1) the ability to own large plots of land for practically no money (since the government provided generous land grants) and 2) the ability to find gold in California.
I believe the answer is: They gave the settlers low prices on better land, 6%, 10 Years credit
The low prices and credit attract many people who seek to change their luck because it provide a lot of opportunities to open new businesses and build new houses. Within 100 years of the announcement, the available land in settlement area was fully purchased.