I don't think we know for certain that she didn't have a bank account or a wad of cash in her pocket. Amber and Katelin's family might not be aware of an account, but that doesn't mean it doesn't exist. Most jobs pay via direct deposit (I don't know about Katelin's) and it's much easier to cash a check (if she receives paper checks) if you have an account at the bank. I realize you can cash payroll checks about anywhere, but not everyone likes walking around with their entire paycheck in their purse and most bills would have to be paid via card or check. Was Amber paying all of the bills? If Katelin's family was helping financially, how were they getting money to her? And honestly, if you're going to up and decide to disappear voluntarily, I doubt that $10 in the grand scheme of things is that big of a deal. She could have easily forgotten about it. Maybe she's got a job lined up at her destination.
I'm still hopping between each side of the fence on this one. I think my heart just wants to hope she's alive and it's causing me to come up with every possible reason evidence points to a voluntary disappearance. Because all of the evidence we're aware of also points to something sinister happening.
Sorry as a fellow Hoosier I'd thought you'd realize that fence hopping is dangerous. 10$ is a big deal unless you're independently wealthy, I don't see that happening in her case.