I haven't had bed bugs before, but I did have a different pest problem, I had a major carpet moth infestation in my damned bedroom, by the time the fluffy cocooned maggot looking things were climbing the walls of the bedroom (when I noticed them) there were thousands of the fuckers under the carpet and hidden behind every bit of furniture I hadn't moved recently.
I bought 2 cans of RAID, taped the windows of the room closed, pulled up the corners of the carpets, put down a thick layer of i think ant killer powder all around the edges of the room (so the little fuckers would have to crawl through it to get out from under the carpet) and in any crevices I could find, then emptied both cans of Raid into the room in 1 go and sealed the door with tape, amateur fumigation! 2 days later I aired it out and 2 days after that I cleaned up the bugs and moved back in from the sofa, that kept them away for the rest of the time I lived there.
I think they make powder for bed bugs too, and I know there is Bed Bug targeted Raid, you would just have to make sure that there are no gaps in the walls leading to other apartments or you will poison your neighbours.
p.s. I'm itching just thinking about bed bugs, I would have evacuated the flat as soon as I found them, but then again, I particularly hate bugs in general, I don't even like sitting on grass.