Bonus for very small net mineral acerage

I have very small net mineral acres in several thousand acres with at least 12 separate tracts of land. I don’t live in Texas but inherited the minerals. Over the years I have been contacted to sign leases and never received anything other than a bonus of $50 several years ago. Doesn’t seem to be worth signing unless I receive a good bonus. What should I ask for? Both leases are near producing wells in Southeast Texas. We could really use the money. Thank you for your help.