Can’t get Event Value in Tag Manager

I’ve got most of the items working with GTM but can’t get the Event Value.
GFTrackCategory – {your feed category – Default Forms}
GFTrackAction – {your feed action – Default Submission}
GFTrackLabel – {your feed label – Default Form: {form_title} ID: {form_id}}

GFEntryData – {json object with entry data} – This returns the whole set of input data for the entire form. But I need only the value to be passed to GA ($500 for example) to make a conversion.

Is there something like GFTrackValue?

Can you provide any help regarding this issue?

Event Value is set within a form, but can’t get it to work with GTM. Custom Variable is also set within GTM.