Sorry but none of those listings mentions what sort of wood it is. You need proper, pressure treated or tanalised timber if it's going to last.
They also use roofing felt which is really bad for harbouring red mite.
Try to get something that's made from proper pressure treated wood and it'll last much longer.
and avoid roofing felt!
We built our own basic run, which is 5 metres by 2 and a half, just using wire, fence posts and tin roofing and it probably cost about that.