Sources close to the ex-rap mogul tell TMZ ... Suge will fork over around $20k to cover the costs associated with burying his mother, Maxine Chatman. TMZ broke the story ... Maxine died last weekend after suffering a stroke.

Maxine's plot -- at Rose Hills Memorial Park in Whittier, CA -- has already been covered. The funeral service will be held there early next month. As we first reported ... Suge's not allowed to attend the funeral because he's an inmate who falls under a category that makes him ineligible to attend funerals ... that category is murder defendant.