It’s variable. Just like any real estate it depends on location and what you are buying.

Cheapest common plot producing grain is the most basic. You can get them for $15. Then you need 5 cards and 50K DEC and a powercore.

Based on the cards you can get 70dec/hr to 3000dec/hr; you do the math.

https://land.spl-stats.com/

This website can help you prepare and optimize.