what is the minimum cost of screen printing on T-shirts ?

Screen print is the most affordable printing method than any other kind of printing process.
So for an example: the printing cost for a single colour will be around Rs/ 3 to Rs/5 per print.
The price varies with multi-colour printing and also the various quality of ink used for
printing.
So, this printing method is much good for bulk production.
The cost also depends on the number of colour used for a particular design.