I've been having an email conversation with someone. The gist is that they want to exhume their mother who died in 2017 and preserve the body themselves. Just as an exercise for discussion, I will list out the cheapest possible path for doing this. I think it's a terrible idea, and the best way to convey that is to list out the required steps:
1. Rent an industrial space. Smallest available is probably 600 to 1000sf at a cost of about $700-$1500/month. Pay for electricity, upkeep, etc.
2. Form a corporation with that address. There is a fair amount of paperwork involved with just keeping any business running.
#1 and #2 are requirements for a number of reasons. Companies will frequently only sell to corporations and will only deliver to business addresses. Also, the various governmental and regulatory entities will insist on a corporation. Basically, nobody will let you store Mom at home in your chest freezer. It just isn't going to happen.
3. Open a commercial account with AirGas or similar.
4. Build a container. Cheapest is probably something like wood and styrofoam. $1000 and 40 hours.
5. Get weekly deliveries of dry ice. Based on https://www.nbcnews.com/id/wbna49201225 your cost would be $700 per month or $8400/yr.
6. Plan for succession. Let's say you keep this up for 30 years. Then what? How do you ensure storage after that?
As an alternative, if you wanted to use liquid nitrogen:
4. Buy a dewar. $50k.
5. Get weekly deliveries of liquid nitrogen. Probably also about $700 per month.
My understanding is that Paul Segall has been stored in this fashion for the last few decades.
One more success in addition to the two above was James Bedford, who was maintained for 15 years by his family before being moved to Alcor. But most of these end badly. Also, in this case, decomposition means there's nothing left to preserve. Embalming solutions usually only delay decomposition by a month or so, but it's been 4 years.