If you could actually find one available from a legal source (now listed as CITES appendix 2), they are probably now in the thousands of dollars each!
Around 1990 I was able to find a pair to purchase. If I recall correctly, 20 years ago, they sold for somewhere around $500-600 each.
You may have better luck in Europe, I don't know the tortoise availability there, but here in the U.S. Homopus species are nearly non-existant by comparison to other species nowadays. I had Homopus signatus signatus, H. s. cafer and Homopus areolatus at one time many years ago. Of the two species, signatus and areolatus, I found signatus to be much more hardy overall than areolatus.