From a point of view of materials and time it is not costly to set up a home laboratory for the purposes of synthesizing chemical compounds or even perform simple procedures in biotechnology - raising bacteria, assaying genes in lower animals, and so on. It is, however, illegal to just forge ahead and do this in most US states or in much of Europe due to the many prosaic, stupid laws that encrust the body politic. Such laws hang around for long after they stop serving whichever special interest wrote them and bribed politicians to pass them. Then there are the cases of mass hysteria that become written into law and continue onward for decades no matter how much harm they cause, such as the drug war.
It is in fact the drug war, and not the normal background level protectionism of licenses and zoning, that turns DIYbio, amateur chemistry and other similar citizen science activities into an expensive and risky endeavor. It should be cheap, but the cost is now all in the risk. The state has shown great willingness to smash first and ask questions later, if at all, and this leads to things like reagent providers only selling to registered labs, requirements to register all glassware, and raids conducted on people who followed all the rules - because the left hand doesn't care what the right hand said, and local police departments make out like bandits from confiscation and auction of assets belonging to those merely accused of breaking laws. Where there are incentives, there will be those who follow the incentives, and the incentives today are very much aligned with less citizen science and more police accusation.
The present state of medical regulation is every bit as bad as the drug war, and indeed very much influenced by it when it comes to thing like painkillers. The massive body of law concerning medicine and life science research accomplishes numerous iniquities beyond ensuring that people suffer more pain at times when drugs could prevent that suffering: it slows development; it makes therapies much more expensive; it eliminates whole regions of development by making them too costly to attempt; it prohibits some classes of therapy by fiat, such as those that aim to treat degenerative aging; it makes it illegal for a dying person to make an educated decision about trying an experimental therapy. And so forth.
At some point the massive wall of laws, all of the forbiddances telling people that they cannot try to make their lives better, will run headlong into the fact that it is becoming ever cheaper to synthesize drugs and the basis for therapies in a home laboratory. All it takes is knowledge and the willingness to undertake civil disobedience: to disregard a law because it is evil and unjust. It has to be said that near every law that touches on medicine in this day and age is evil and unjust, and the costs they impose in their aggregate cause great pain, suffering, and death. What might have been accomplished without the ball and chain of regulation is invisible, however, and therefore easily waved away by those who claim that regulation is necessary. Everyone takes the present state of affairs as the way things are and looks little past it.
Unlike recreational drugs, it is clear that the costs and the benefits for manufacturing your own medicine are not yet at the point of spurring people to action at the level of small chemistry or biotech laboratories. The knowledge is still too specialized, the complexity of the work too great, and the benefits too narrow. This will change, however, and think it will largely change on the benefit side of the equation. For example, consider mitochondrially targeted antioxidants like SS-31 and SkQ compounds: synthesizing them is an exercise in organic chemistry that is many steps in sophistication above the bucket chemistry of a recreational drug laboratory, but I have to imagine that there will be a market for these things once the public starts to appreciate that they seem to have significant effects on aging tissue. SS-31 produces endurance benefits in older mice when tested, and that's probably a draw if it does the same for people. The athletics community certainly includes an underground of experimental biochemistry, one of the consequences of all the money floating around there.
Targeted antioxidants shown to reverse some aspects of aging and extend life in mice are a trivial exercise in comparison to what is coming down the line, however. It won't be too many years from now before researchers can describe exactly how to repair and replace damaged mitochondria, construct infused enzyme solutions that destroy specific metabolic waste products that contribute to aging, and so forth. The future of medicine to treat aging and extend life will consist of a whole range of precisely designed proteins like the waste-product-chewing enzymes that can be manufactured in an appropriately equipped biotech lab. The cost of materials will continue to fall, the knowledge needed to perform the work will continue to disseminate, and when the upside of civil disobedience is rejuvenation and more years of healthy life then there will be a whole lot more civil disobedience.
In actual fact, I think that the scenario of distributed scofflaw medical manufacture will happen along the way, long before SENS-like rejuvenation biotechnology is at a point where portions of it could - in theory - be performed in a sufficiently well equipped home laboratory. Something better than SS-31 will emerge, or at least something better equipped to catch the public imagination, and grey and black markets will bloom. I'm looking forward to it: the present system of medical regulation is ugly, repressive, and costs lives: the sooner it collapses in the face of ubiquitous disregard the better.