Can I buy a setup without a plan?
Yes, in two cases. If you already pay for a Zapped plan, you can buy any setup that fits your plan on its own, from its setup page, without changing your plan. Email Signature can be bought on its own by anyone, even with a free account. Every other setup is ordered together with a plan: pick it on the plan page, and the setup is ticked for you. If your plan is too small for a setup, the button takes you to the plan change first, where you see the new price before you pay, and then straight to the setup. A plan an administrator gave you by hand, or a paused plan, can still buy a setup on its own at the full price. A setup bought on its own costs the full price, or the yearly price in the first 30 days of a yearly plan. A quote or an invoice is optional, you never need one to pay.

