There are numerous organisations that fund sociological research including charities and businesses, the largest funder is the government
Money
generally the more in-depth the method the more money it costs. Doing your own primary research tends to be more expensive than using secondary sources
Time
generally the more in depth the method the more time consuming it is. Also doing your own primary research tends to take longer than using secondary sources
Access
are the opportunities for researching a group. Some groups may be less willing to take part in research than others or harder to reach. Some institutions may also be more difficult to access than others for example schools.