There is a huge range of pricing for both of these types of machines, depending on the product structure, product features, machine speed and machine consistency. 

The common range of prices for European or US diaper machines would be from $2,000,000 to $6,000,000 - you can pay more. Chinese machines cost from $300,000 to $1,800,000.

Second hand European and US machines are often available, and would range from $300,000 to $1,000,000.   

Sanitary napkin machines range from $80,000 to $1,200,000. The lower priced being slow and inflexible machines producing a simple napkin. The lowest priced European machines cost circa $400,000. 

There are also manual diaper machines available at costs below $20,000, but these require high labour input and produce very few diapers that will be at a low quality level. Not recommended

Please ensure that you have checked the potential profitability of such a machine with me before purchasing