what is the allowed monthly income for some one on Medicaid getting SSI checks?

Depends upon whether it is earned income (wages or self-employment) or unearned income (any other type of income).

If you receive the monthly maximum SSI benefit of $783 the unearned income of $805 would make you ineligible for a monthly SSI benefit.

If you receive wages all you have to do is multiply your monthly SSI benefit by two and then add $85.  The result is the amount of earnings which would result in zero SSI benefits being paid.  Example:  Your SSI benefit is $783 x 2 = $1566 + $85 (the $65 monthly earnings disregard + the monthly general $20 disregard) = $1651.

SSI doesn't county the first $65/$85 of earnings + 1/2 of the amount over it.  Example:   You earn $500 - $85 = $415.  Half of $415 = $207.50.  The SSI benefit would be reduced by $207.

As for Medicaid entitlement - I would have no idea except that in all but 11 states if a person is entitled to an SSI benefit (even if it is reduced) they are automatically entitled to Medicaid.  In the 11 states where it isn't automatic you would have to contact the dept of social services and ask.  If not automatic you would have had to have filed an application for Medicaid with the Dept of Social Services.

I was a SS claims rep for 32 yrs.

Depends. My state didn’t expand Medicaid. So for one person without kids the limit is less than $300 a year. Make any more money than that and we can’t get Medicaid. In states that did expand Medicaid, I think the limit is less than $14,000 for a single person with no kids.