How can I pay for a subscription for my colleague?

Need a Bronze or Silver subscription for my work mate because she cannot have subusers of my account, right?

You have a Gold account and 22 sub account users. 

If I understood your question correctly, you want to upgrade one of the sub user accounts. Is that correct?

Inside of this guide, you can find how to upgrade account:

How to Upgrade My Account

This should be done from the sub-account.

However, I am not sure why you want to upgrade the sub-account. Why don't you just add a new sub account user of your account M732burke? Please note that if your sub-user account adds a sub-user account of his/her account, he/she will not be able to share the forms that you shared with them. The sub account user will only be able to share the forms that were created in his/her account, with his/her sub account. 

Katrina.Bowling@ece.alabama.gov is one of my sub-users. She needs to create forms and create sub-users and needs a large amount of forms and views and submissions.
I have shared with her, as a sub-user of my account, all of the forms in the ECE folder. She should have view and edit capabilities there. When she is trying to create a new form, it is telling her she is over the limit for creating forms.
To what level should I upgrade her sub-user account to give her more capacity? How many forms may she create as a sub-user of my GOLD account?
Marcia Burke (M732Burke)
...

She is unable to create new form because she is trying to create new forms inside of My Forms folder. You as the main account also cannot see the forms that your sub account users are creating inside of My Forms folder on their accounts. 

You have a Gold account and you can create an unlimited number of forms. Your sub account users can also create an unlimited number of forms, but only when they are creating new forms inside of Shared with you folder.  

Please tell your sub account user to select Shared with you folder in her account and then to create a new form. 

Also please check this guide:

How to Share Forms with a Sub-Account User 

The sub account user only has to upgrade the sub account if she wants to create a new forms in her account.

To create forms as a sub-user of my account, she has to transfer ownership of forms she creates to me. She cannot delete one of these after transferring ownership to me. When she goes to create a new form, it won’t create inside my M732Burke
shared with her folder. It creates it in My Forms, then she has to transfer ownership to me. Then she can’t delete it. I tried to see the form she created so that I could delete it and can’t find it anywhere.
Also, when she tried to create a form, it gave her a “out of submission storage” error message, so I logged in as her, and upgraded her storage to get her through a project today. Since we work together and are working for a state agency, it is easier for me as a private contractor to pay for the subscriptions. The process to get her an individual subscription paid for by the organization is a huge paperwork/contract review nightmare.
So I will probably just log in as her, and get her a bronze subscription of her own and hope that will be large enough for most of her individual projects. For larger projects, she will just have to deal with the inconvenience of being a sub-user of my account.
Does this make sense?
Thanks for trying to help.
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To clarify, if you add a sub-account user , you need to be the main account user. You are the one creating the form and linking it to your sub-account.

Here is a guide to know more about How-to-Share-Forms-with-a-Sub-Account-User

Hope this information helps.

Please let us know if you need further assistance.