Hi Boban! You can achieve this using custom states. Essentially, you'll add two prices: one for the subscribe & save and one for the one-time purchase, with each price having its own custom state.
The one-time price will have a default state where the price will be "$29.99" and a custom state we can call "not slashed" where the price will be "$29.99".
By using the activate state interaction, you can activate the "default" state when the "Subscribe and Save" option is clicked, and activate the "not slashed" state when the one-time purchase is selected.
For the subscribe price "$23.99," create a custom state called "hidden" to toggle its visibility across all devices. Use the activate state interaction to switch to the "hidden" state when the one-time purchase is selected, and revert to the default state when "Subscribe & Save" is clicked.
For more details about custom states, you can check out this doc. Let me know if you have any questions!