Which is better and is there anything else under $50?
Thanks
302usb doesn't have a full 48v for phantom (something like 15v) and may not work with all condenser mics. The Alpha has no phantom power for mics and wound need an extra box to supply it. Neither in my opinion would be a good choice. Depending on your needs, best to stay away from mixer type interfaces.
I have no experience with the suggested interfaces, but likely what I might consider in that price range. Also look for used bargains of a decent interfaces.