Yep. For example, Spirit and Opportunity were part of the Mars Exploration Rovers mission. 2/3 of that mission's total cost was the development, manufacture, and launch of the rovers themselves. Which more or less "per unit" works to 1/3 of the total mission cost per rover. The other third of that mission cost was staffing for the (15 year) ongoing mission from when it passed the initial mission parameters to when opportunity finally was deemed dead in 2018.

https://www.planetary.org/space-policy/cost-of-the-mars-expl...