I was looking for the second HW wallet (I already own Trezor One for BTC, ETH) to hold my alts (like ADA, ATOM, NEAR etc.).
I thought to get Ledger nano s+, but are there any open-source alternatives for +/- the same price?
I would not waste any money for storing bunch of altcoins on hardware wallet, especially if you already have a Trezor wallet you can use for that.
If you still decide to buy one more hardware wallet, I would never buy cheap Safepal wallet for sure.
Wallet that is offering some improvements compared with Trezor with higher price would be Bitbox02, it's open source wallet with secure element and it supports altcoin.
There are other options but they are mostly Chinese Trezor replicas or they don't support altcoins, so they are not for you.