I think you should have your cousin do more research on dogs before he goes out and gets a "cheap" one. Raising dogs is expensive. Premium kibble can run as much as $40 per bag and a boxer can go through a bag or more per month. In the first year there are lots and lots of trips to the vet for vaccinations (approx. $150 per round x 3 rounds), spaying/neutering (appx. $200), bedding, toys, grooming supplies, crate, leashes and collars, etc., etc., etc.
I would estimate that in the first year of owning Maggie (I got her at 8 weeks) I spent well OVER $1,500 on all of this plus more. Trips to the vet for anitbiotics when she got sick, infections and things that all pups get which need treatment, etc.
A "cheap" pup will not lessen any of these expenses. Unless your cousin is prepared to spend this kind of money raising a dog and giving it the proper care and maintenance, I would suggest to him/her that they wait until they can better afford such an expense. It isn't fair to the dog if you are not prepared for all that is involved in raising one.
Respectfully,