Any crypto wallet in which you have full control over your private keys is a better option than any online wallet. I think this is something that most people who understand the term "not your private keys, not your coins" will agree with. If it is financially challenging for you to buy a hardware wallet or other computer/smartphone the only alternative is to start using some desktop wallet.

If you take all the necessary security measures, which include having a malware/virus free computer + to verify wallet file before installation, then you can have a relatively secure wallet for free even on Windows OS. For extra protection you can use Linux Live CD/USB as mentioned by ranochigo.

Everything you need to know about How to Safely Download and Verify Electrum