To get rid of roaches easily, mix up some Murphy's Oil Soap or equivalent, your preferred bug spray, like Black Flag or Raid, and water. Maybe in a 20/3/77 ratio or thereabout. The water helps spread the poison, and the soap both reduces the surface tension, improving penetration into seams, and breaks down the oils that the bugs feed on.
To get rid of fleas, put soapy water in a metal pie pan (even the throwaway ones that come with premade crusts), and place them under a night light. The fleas will be attracted to the heat and light, and will sink and drown in the soapy water. To PURGE them, get some sort of powder, and walk it into the carpet in every room.
To get rid of bed bugs, just buy the spray made specifically for that purpose, and saturate everything. Do it ASAP, for your own sanity. I am not joking in the least, or overestimating the psychological damage they can cause.