There will be two types of cell lines. One is extracted from living animals, and the other is extracted through butchering. The latter will provide a great deal more meat more cheaply (as these cells can only divide so many times).
So it depends on where you want to draw the line. If you don't mind taking, say, 1/1000th of the life of a cow to eat a burger every week for the rest of your life, then it is fine either way. If you don't want any part of a dead animal on your hands, then you will have to go with the more expensive extraction method.
Of course, if you don't want ANY part in any animal death, you should know that pretty much everything you use has animal parts in it somewhere. Hell, tires are black because of carbon black sourced from charred animal carcasses.