Beginners play with five strings. A five-string piano is more expensive.

Fuji root NCJB5- 10R (cost-effective five strings, Fuji root world famous factory)

The five-string rock bass cruiser owned by Warwick is also good.

Fender 0 19 7802 markus miller's signature (my teacher's style, the piano is great but a little expensive).

Fender 0 19 0760 700 American jazz bass (this piano is also good, a little cheaper than the one above)

In fact, four strings are enough for beginners, and five strings can be used for advanced students.