We've run into a similar issue with setting up our online bookings. It seems there is no native option in Jobber for drop-down selection booking options (yet), so our work-around for this was to create a separate Online Booking Service (adapted to your junk removal) called Online Booking - Curbside Pickup setting the price as the minimum (or maximum) charge, and setting the description for this service as something like:
Online Booking - Curbside Pickup
We'll pickup your items curbside - charge varies based on item being picked up, click See More below for a full list of items and associated curbside pickup fees. Please note on the next page which item you'd like to have picked up.
Bicycle - $18
Canoe - $45
etc...
It's not a perfect solution, but could be a viable work-around for you until more online booking options are integrated.
Hope this helps :)