SoFi Money, which is their cash management program, includes an optional "roundup" feature that passively transfers part of a dollar of your own money into a savings-like account (a "Vault") for each debit card purchase. I assume it's a clone of the better known "Keep the Change" program at BofA.
Once or twice a year, SoFi runs a promotion where they match Roundups. In other words, they give you between zero and 99 cents for each debit card purchase, depending on the amount. For example, if you make a purchase of $10.05, they move 95 cents from your main Money account to your Vault and they give you another 95 cents. They launched one of those promos last week. It maxes out at $50 of free money and runs through December 31.
I did one of these before. It can take some fiddling to get all the settings configured just right. It's tempting to look for creative ways to maximize the earnings and earnings rate, but I would advise caution. I was pretty aggressive, and that might have landed me in SoFi's doghouse. They never communicated any displeasure directly, but I wasn't able to participate the next time they ran the promo. It's working for me this time, but I plan to particpate less enthusiastically than before.