Ref: Apastamba shrauta sutram prasna 10
In yajna, Somapravakaha is the person assigned to invite learned vedic scholars as ritviks. When he approaches the scholars they ask :
" ka ritvjaha ke yajayanti kacchinnaheenaha kachinna nyastamartvijyam KACCHITKALYANYO DAKSHINAA" - who conducts the yajna, who are other ritviks invited, is the yajna going to be without any shortfall, is the dakshina proper and abundant ?
Then only they decide whether to participate in it or not. Providing suitable and proper dakshina to the brahmanas is very important in yajna, and being the custodians of yajna, it is also the duty of the brahmanas to ensure beforehand that proper dakshina is provided.
Dakshina is considered to be consort of yajna - " yajno gandharvasthasya dakshinaapsarasaha".
This applies to learned scholars and not to " priest by day and auto driver by night" kind of purohits.
If you pay peanuts you will get only monkeys.