Okay…I apologize - had you been that specific I would have responded accordingly. For you reference, just to get a ballpark, check with DocVerify - I believe they’re doing it - you can see what the monthly/yearly fee is going to cost you - yes you can shop around but you can at least get an idea.
As to this question - “what would be the corresponding amount I should charge for my services to make it profitable” Not sure about the law in Ohio but here we can charge $25 per online notarization; not sure if additional service charges can be assessed to cover equipment & other monthly charges.
Hope this helps.