the nebulizer is a small part of the equipment which sits at the patient
end of the circuit, what you probably need is an air compressor (the device
that pressurizes the air and pumps it through the compressor) you should be
able to get one of these from a hobby or hardware store (used for spray
painting etc) much cheaper and more available than a device manufactured as
medical equipment. You might also consider a cylinder of compressed air,
depending on how long it needs to be in use.