I just ordered a kit for my puppy 2 weeks ago and the price is $65. It is really easy to do and then you know what to expect.
Basenjis can have issues like EPI, IPSID, and IBD. Many times they manifest very similarly and so it can be just process of elimination trying to rule out or rule in what disorder it is.
How is his appetite? How often and how much is he pooping? If he is pooping a lot and a large volume each time, he may not be getting much out of his food.
I agree with Pat that after you get his results from the vet, if nothing really stands out, you may want to try a limited ingredient food like Natural Balance or Wellness Simple Solutions. These foods are good for sensitive stomachs because they have less ingredients that may trigger a reaction and they are highly digestible so the dogs get the most out of them.