I do like cyanotypes, especialy toned with coffee or tea. Bostick-Sullivan sells a kit for doing them that works real good.
For a negative though, it makes sense to spend the $1 on a piece of film from Ilford/Arista/Foma (or more from Kodak). You just shoot less compared to 35mm or 120.
Cyanotypes aren't free either. The non-buffered paper for that costs something. Tintypes and liquid emulsion probably cost more than doing images with film.