Geodon is not a mood stabilizer. It is an antipsychotic.

Over the summer I ran into a similar issue. The pdoc told me lithium or tegretol re the cheapest mood stabilizers here at $4-$10 a month depending on pharmacy. I refused both. I take trileptal now and spend about $60 before I reach my deductible. As food antipsychotics, I don't know which would be cheapest. Risperdal was pretty cheap. I didn't try any others.