You don't need a HHW in order to achieve cold storage for your bitcoin.
Shocking I know.
If you only have $500 worth of bitcoin, you probably don't want to spend $50-%250 on a HHW.
If you want to stack sats but you don't want to do it in a hot wallet you'll need two devices... Either two mobile phones or a phone and computer is fine. If any of the devices are Android, I would suggest flashing LineageOS, GrapheneOS, or CalyxOS to it first. This will help to "de-Google" the phone and increase your control over the hardware. That's for a separate post though and it's not a necessary step here.
Here is a 5-min video that covers the following method in detail utilizing Samourai and Sentinel.
For creating a wallet you can use Samourai, Envoy, Blue Wallet, Stack Wallet, or Sparrow. For the WoW (watch only wallet) you can use Sentinel (android) or Blue Wallet (iOS). See my previous articles for links to everything.
The flow looks like this:
- Generate a wallet whilst in airplane mode on device A (Samourai, Blue Wallet, Stack Wallet, Sparrow can all do this).
- On device B, import the xPUB, zPUB, or yPUB.
- After you've done that, delete the wallet from device A. Or keep the device offline and keep the wallet there.
This isn't for spending it's for stacking. One could spend even while the wallet remains offline. Simply create and sign the transaction, and send it to the Sentinel or Blue Wallet for pushing out to the Bitcoin network. By staying "cold" this would increase your security, but not your privacy. I would recommend using whirlpool first and then using the post-mix tools on Samourai or Sparrow. This necessarily requires the wallet to be hot.