Topic: ferret consuming too much memory

I'm currently hosting with hostingrails.com's pay as you go plan, which charges per MB of virtual memory used. My app uses, ferret, and this requires ferret_server to constantly be running, which constantly is using around 50MB a day, which all by itself costs me $10.20/month with their plan. Does anyone have any ideas of somehow reducing this, or maybe using a different less memory intensive search system?