Sell
One of the so-called 'homelands' in South Africa is Venda. This area is located in the northeastern part of South Africa and borders Zimbabwe. Venda borders Kruger National Park and is therefore well-known to many tourists visiting the park.In South Africa, there were ten more or less autonomous territories called homelands. The name Venda came from the original inhabitants, the Bavenda. The capital was Thohoyandou.
Venda was granted a form of self-administration from February 1, 1973, and a form of independence from September 13, 1979, but no country in the world has ever recognized Venda as an independent country. Nevertheless, postage stamps have been issued since September 13, 1979. Many stamps feature images of the flora and fauna of this area.
I found them exclusively on first-day covers. That is how they were sold to tourists.
Like the series on forestry. From sowing, through felling, processing into beams and slabs, to the construction of wooden buildings. On April 27, 1994, Venda, along with the nine other homelands, lost its independence and was reunited with the Republic of South Africa. The homeland was never recognized as an independent country; therefore, the stamps are not recognized as official postage. Nevertheless, due to their often beautiful imagery, they are included in the collections of thematic collectors. 
“not recognized as official postage.”
I have dozens of used ones from Venda and other home countries. From bulk goods and dime books.
They are also neatly listed in all catalogs.
http://www.stampcollectingblog.com/stamps-of-south-african-homelands.php
Though these stamps were not officially recognized by most postal authorities, they were generally accepted on international mail. As such, they also appear in all major stamp catalogs with the stamps of South Africa.
When homeland system was terminated in 1994, each state had issued roughly 300 different stamps. AFAIK, there are no huge rarities with these stamps and they are somewhat easy to find (especially in mint condition).
I checked the British eBay website and saw that dozens of mint series are being offered. Furthermore, there are a lot of First Day Covers and a single series with a 'request' cancellation. Not a single stamp has been used 'normally' or is on a postal item. Stamps cancelled with unrecognizable postmarks are not collectible to me. For me, the list of countries affiliated with the UPU (or that have been affiliated) is the deciding factor. The fact that stamps from the home countries are included in catalogues is nice, but it proves nothing!
On Delcampe and via Google, I do find mail from Venda, Bophuthatswana, Ciskei, and Transkei.
Lars, I followed your advice and checked the Delcampe website. Only the 43 pages of VENDA. Two envelopes appeared there, one with a series of stamps cancelled with an indefinable stamp and addressed to 7448 Big Bay, and a second envelope from 2012 (!) with combinations of stamps from Transkei, Venda, and RSA (Republic of South Africa). The cancelled individual stamps mostly had indefinable cancellation marks or FDC (soaked-off) impressions. I did not check the other home countries.