Depends where you are in the world - Some chemicals are readily available, others can be problematic. For example, to make a D-85, paraformaldehyde is required which is almost unobtainable here in the UK.

Fortunately, Ansco 81 and DuPont LD-2 are formaldehyde free, so can be mixed quite cheaply at home. Some experimentation is required to see if you get the results you're after.