These are guesses, but somewhat educated guesses:
I don't know the "high" end domestic, but I'm guessing Rock might pay the best, and probably around $30k and up. Maybe someone has high as Sevilla or Mancebo are over $50k. Floyd might be in that range, but he's also probably in a lot of debt.
Most bottom end pros make about $15k a year, maybe less, maybe more. Depends on how well the team does, for extras, wins, primes, etc. It's a lot of sleeping in vans and on couches, hostels or stuffing 6 guys in a hotel room and sleeping on the floor, and all-you-can-eat meals at buffets, going to a pizza place just before closing and asking what they have left over, bagel shops in the morning asking for yesterday's leftovers, etc.