Mescaline, or any cacti alkaloid spectrum can be very cheap to extract. If you grew the plants from seed or even given seed and proven cuttings. I don't trust industrial solvents and don't trust distilling diethyl ether but it is cheaper to do that in the long run.
There are alkaloid differences from cutting to cutting and variety to variety. Methods of prep change alkaloid spectrums. I have experience with cacti and found extracted peyote to be the best and most colorful. Crude home grown trich hybrids were darker, almost more 'evil'. Maybe it was just me, the trip or people that brought their vibes around the plants. Perhaps an extract could have purified the experience.
it still isn't cost effective to extract for sale.
that also has to do with the scarcity of actual Peyote and the years invested in growing.
Other cacti can suffice, I've used San Pedro, but then the yields are not as great so it still isn't cost effective as a money making venture.
most people do as you have, extract it for personal use.