IMO, I dont think hardware wallets are expensive at $100 or less. Of course if there are more options under $100 will be good, it will benefit users with lesser budget or newbie who want to try. However, security is very important. So, dont lookout for price but security first.
Less expensive options are coming. I can only suggest to look out for special deals by the manufacturers and/or to simply wait for older models to be made available at a much less expensive price.
For instance, there's the Trezor One, whose more expensive successor is the Trezor Model T. Both models work just fine. As far as I heard the former will be made available at a very affordable price in Q1 2019. I predict that more affordable hardware wallets will get a lot more people interested in using hardware security to protect private keys.