Zambia visa:
Many passport holders no longer require a visa for entry to Zambia: https://www.zambiaimmigration.gov.zm/nationals-who-dont-require-visa/
For those that do need a visa, this can usually be purchased at all borders and international airports: https://www.zambiaimmigration.gov.zm/nationals-who-require-visa/
Some nationalities need to get the visa prior to arrival at the border: https://www.zambiaimmigration.gov.zm/nationals-requiring-visa-prior-to-travel/
The cost is U$50. A double entry visa is U$80
Univisa:
This visa covers both Zambia and Zimbabwe and can be obtained at Lusaka and Livingstone airports as well as the Kazangula and Victoria Falls land borders.
The cost is U$50
Nationalities that cannot obtain a visa for Zimbabwe at the border are also not eligible for this visa and need to get both visas separate.
If you are on a tour coming from Malawi you will not be able to obtain this visa.
For tours starting in Lusaka and visiting Zimbabwe you can obtain the visa at the airport.
The Zambia visa is a full page visa.