What is the average price for about 80 feet of 4-wire 240 wiring for a hot tub?

You can't use it anyway. Individual conductors such as THWN with an insulated ground run in conduit.

There is no average price for anything.

The size and type of cable you need has to be defined. You have not given us enough information to work with.

For example, what is the distance you need for this cable. Do you need copper or aluminum conductors?

Is the hot tub an indoor model or an outdoor model

You first need to tell us what "4-wire 240 wiring for a hot tub" is exactly?
All wiring and all hot tubs are not the same.


For the indoor portion of wiring to a hot tub, in a single family dwelling, cable is fine to use. It's the outside portion that required insulated conductors in conduit without exception.