I didn't see any mention from the OP that the basses are smaller than the usual "3/4." Assuming that's what they are, I'd say there's far too little information here for a truly informed answer to be given.
- Were the Wilfer and Shen both seen at a (the same) bass shop?
- Is the Wilfer really "battered" or just showing normal cosmetic deficiencies? The judgment of a novice vs. someone experienced is often very different in this regard.
- Is the Wilfer structurally healthy (as judged by a luthier)?
- Are either or both basses offered with other accessories (e.g., new strings, bag, etc.)?
- Can you provide pictures of the Wilfer?
If, the Wilfer is truly battered, not offered with any type of backing from a luthier, and not offered with, at least, new strings, then I'd say the price is high. On the other hand, if it's structurally sound and, overall, healthy, and backed by a reputable bass shop, it may just be a fine deal, especially if it's offered with new strings.
The Shens are solid entry-level instruments with a good reputation. The Wilfer may just be a gem. No way to tell from what's been offered here.
bassmom123, I suggest that you establish a relationship with a real bass shop. The best assistance you can get in your shopping would be provided by a good teacher and/or experience player. If your son has a teacher that you trust, then it's well worth paying him/her to go along with you. Consider it "lesson time."
People online, even members of this esteemed community, can't really provide meaningful help when presented with a "Should I buy this or that?" when minimal details are provided. I'm not being critical. Rather, I'm trying to save you headaches by suggesting a path to what will be the right decision for you.