Keystone's headline offer is aimed directly at one group: "Ledger users upgrading to Keystone can receive an exclusive 20% discount" - stated on the Keystone homepage, with the "Upgrade Now" button leading into their shop. No code and no end date are published on the homepage, so the discount is presented as an offer rather than a code here.
The second documented offer is the bundle: "Keystone Bundle PackSaved $23" - Keystone 3 Pro + Keystone Tablet Plus + Wallet Pouch starting at $232.90 USD with free shipping. Note that the bundle is on pre-order (the store says it ships within 4-6 weeks). Free shipping applies to orders over $30 to Europe (except Switzerland and Norway), the USA and Australia. Keystone Care+ warranty coverage can be added at $50 per year tier (1-3 years).
How to redeem
The Ledger-switcher discount runs through the homepage's upgrade flow into the shop; the bundle discount is automatic in the cart.
Re-check
Daily. If Keystone publishes a checkout code or an end date for the switcher offer, this page gets it with the source quote.