You should be able to log in directly into the Store without associating that account to your local account. That should be the default in 8/8.1, I don't know i

You should be able to log in directly into the Store without associating that account to your local account. That should be the default in 8/8.1, I don't know if it applies in 10 but it's exactly how you can get universal apps while on a domain account.