According to Sofi, you can select a set amount of percentage of your paycheck to be converted into any of 30 available crypto coins (e.g. Bitcoin, Ethereum, Litecoin) automatically. There is a minimum $50 but you can change the amount at any time.
If you already have an Sofi account, this is a no-brainer. If not, this is definitely a reason to open your own account there.
If you are interested in getting your credit card cash back in Bitcoin, check out this article.