I haven't had an issue with the non-BlackVue branded SD cards. I'm running a SanDisk in mine (DR650GW-1CH). As long as it's a class 10 card it should work. At the time I got mine, is was far less expensive to buy a larger SanDisk SD card and not use theirs included vs. upgrading to the larger...
I understand you specified inexpensive, but I've had really good luck with the BlackVue cameras. Again, more expensive but if you want the added features of 4k, wifi, and dual channels they are a very good product and you get what you pay for. Check out The DashCam Store, they're good to deal...