Yeah, I'd say if you can get them for a couple/few hundred bucks you could have some nice axles to build. Basically for your YJ all you are going to need front and rear is spring perches and shock mounts. You don't need all that sway bar and trac bar junk.
Those are going to be a different wheel pattern than your YJ so you'll have to either get spacers or new rims when the time comes to install them. But with some clean up and paint you could be in business.
They are also about 6 inches wider overall than the YJ axles. So you have to decide if that's something you would want to deal with.
Basically when it comes to building junk yard axles you just have to decided if you want to commit to the project and then go for it. When it's all said and done you could end up being 2k into those axles or you could end up being 1k after the purchase price.