I'm in the UK so went down the local car spares shop. I don't think its a difficult item to buy.
You get a plastic cone to help stretch the boot. Warm up the boot in hot water, put loads of WD40 or equivalent on the joint and cone and pull the boot over the cone and cv joint.
When buying them, just make sure the sizes of the boot match the diameter of the CV joint at its widest and the shaft at its narrowest end.