Most importantly is the issue of prejudice and race. Walter's family is black and has moved into a white neighborhood. The neighbors have sent emissaries to "buy" away their home so they will move to some other neighborhood. Pride keeps Walter and his family from taking the money. They will stick it out in this unfriendly neighborhood.
Aside from the issue of racism, the play addresses the issue of poverty and wealth. Even though the play suggests that the family is doing well and that Beneatha will be able to go to school and marry well and they have moved into a nice house in a nice neighborhood, many people in the USA were still living in poverty. The wealthiest were able to afford attorneys to avoid paying taxes on their wealth and the burden fell to the working class to pick up the slack. The loss of the money Walter is playing with effects the entire family's livlihood.