@JPmbogo
As other have stated.
Location. Not only for buffalo, but for other species as well.
Location, mainly means - Country, as general guideline
If you are new in African hunting, try to get the first orientation bearings on price distribution, per country. Not only for buffalo but for other species as well
In general - for safari hunting, the rule is:
If you hunt on a hunting farm (Namibia and South Africa) the prices will be most economic.
The difference is, again in general, Namibian farms most probably will not have buffalo. This leaves South African game farm.
So, at the moment, most probably the most economic offers will be South African game management farm.
Second consideration is this:
Do you want to hunt in the fence, or out of the fence?
South Africa.
There are very large hunting farms, high fenced, which support free roaming, self sustaining herds.
On the other hand, there are opposite examples.
For hunting out of the fence, there are other countries, with few exemptions.
Third consideration.
Do you want to hunt buffalo bull, or buffalo cow?
Cow can be significantly more economic options.
Finally, if you want to hunt in wilderness (total African wilderness), day rates will be much higher, and overall hunt expense will be much higher.
For wilderness hunting, check Tanzania, Zambia, Zimbabwe, North - East of Namibia - Caprivi strip (Zambezi region).