This could be relatively easy if you are willing to live with a few limitations. They are: AC operation only, single speed (no slewing) and an equatorial mount.
If those limitations are ok with you, then an AC synchronous motor (a clock motor) with a lot of gearing will do the trick. This is what mid-to-high end telescopes came with before microprocessor-based drives became popular.
You can run such a drive with batteries if you add an inverter that is frequency accurate. You can also provide some slight slewing (around half-speed to 2x speed) if the inverter frequency can be adjusted. I built such an inverter back in the 90s for under $30 (to drive an existing Meade clock drive).
If you don't have an equatorial mount (like a Dobsonian mount), then it is much more difficult. You would need two motors and a computer control. Brushed DC motors with encoder feedback would work best. That would also allow you to slew at high speed.