Welcome to the madness!
Fish finder or bait tank? BOTH
Of course if your budget will allow........
If you have to pick one based on your budget I'd go with FF because you can fish plastics, irons, or frozen bait.
BUT..... you can also get a bait tube, they arent expensive at all and then you can have a place to keep your macs alive until you get the funds for a tank with pump.
See ya OTW,
Mike