I'm just starting out, so I'm trying to be pretty strict with cash only purchases. If I do make an online purchase I deposit the amount of the purchase from the appropriate envelope to help keep us accountable. I think transferring from a secondary account, or dipping into my cushion, would allow me to easily "justify" purchases I don't really need. If I keep it within the limits of my envelopes I'm more likely to make better decisions, personally.