What do you mean by a 'dry ice machine'? Dry ice is solidified carbon dioxide, and needs specialist equipment to reuce the temperature or compress the gas until it reaches a solid state. There never was, and I don't suppose there is now, a machine which would produce dry ice other than the rather complex and certainly non-portable ones used by the chemical companies who produce this form of carbon dioxide, which is not the easiest substace to handle in any case
What purpose do you need it for? If it is for a stage production, many theatrical hire shops or disco supply shops can hire you one and advise on dry ice suppliers.
Many stage ones are fairly large and on wheels. They are basically like a big cube on wheels that boils water, you place the broken dry ice blocks into a wire basket which then winds down like a chip fryer into the water. The dry ice is then pumped out of a tube attached to the machine.
One popular one in theatres is the LeMaitre Pea Souper.
If you want to make blocks of dry ice, there was a machine for stage use for this. I saw it about 15 years ago, but unfortunately I cannot recall the manufacturer or name of it.
A portable dry ice maker allows you to produce dry ice anytime and almost everywhere. Some models of portable dry ice makers can produce 1 lb- blocks of dry ice within a minute.