Cannot afford aldara (imiquimod) (or generic) in the slightest bit; pharmacy said $200+/treatment. Warts are spreading fast. Is there an alternative?

Yup. Aldara (imiquimod) is crazy expensive. There are many treatments that are far more cost effective including cyrotherapy, podophylin, cantharidin, and others.
Salicylic acid. Some less expensive options are podophyllin, salicyclic acid (compound w, duofilm), canthacur.