A Trezor only costs ~$95. You don't need to have $350k worth of Bitcoin to make it worth buying one.
Exactly this. I bought my first hardware wallet when I had $300 worth of BTC. They are a great investment.
Note that Ledger currently have a Christmas sale on, so you can pick one up for 69.99/£69.99/$65.65 through their official store here (
https://www.ledger.com/collections/all-products) or one their licensed retailers here (
https://www.ledger.com/pages/retailers).