Honestly, it's hard to say. Lowrey has been producing organs for several years now and they are constantly updating their technology and improving. The M-375 is indeed a great organ, it has decent animation sounds with the flutes, and the rhythm section is not bad for an organ of its age.
Honestly, it has the old technology for the ez-play today music so in the eyes of that aspect, its not worth anything. You could possibly sell it to a person who is looking for a practice organ that lives in a smaller place.
As for value, no more than $200
A serviced, functional and cosmetically clean Lowrey NL-30 parade organ could be worth at least $300-500 in a good market on the right day. Your biggest hurdle with this will be finding a local buyer, or, at the very least, someone willing to pay for freight for this vintage music machine. Of course, condition and functionality are the greatest factors affecting the price. Make sure it is clean and fully working for the best possible price.
there is no standard, potency may be affected by many factors. somethings to consider how long after the exp date its been. has it been stored properly. was the container sealed at all times. temperature. there is too many factors to give a good answer. start small, work your way up slowly. better yet dont get high with that stuff try helping someone it'll make you feel good too