It's good to know what your buying. The cost of a hit of LSD is about 2 cents to make, while growing the real thing (mushrooms) takes time and expertise.
I have seen so many guys with bags of Safeway brown mushrooms I've lost count. These are the shrooms your mommy puts on your hamburger, sprinkled with LSD. Google these shrooms and KNOW how to recognize the mushroom your going to consume. I grew cubensis for 5 years in 100 lbs. flushes. I was able to do inoculation in the labs of a collage, as sterile conditions are necessary. We dried the shrooms into 1 lbs lots.
This was in 1977. Point being , it's complicated , time intensive, and costly. So make sure what you get isn't BS.
As everyone is different,"and" there is a difference of content between mushrooms, there isn't a general law on how much to take.
Incidentally , I got tired of being run out of farmers fields, down on my hands and knees, looking around cow pies, angry land owners. And that type of mushroom is called Liberty Caps -- not very clean.. not a good representation of what a good trip should be like. The shrooms I grew had white stems and brownish caps. These mushrooms show a purple color if bruised....so look for white stems and purple bruising. I grew 4" to 6" shrooms. For a first trip I would take one stem. (if it's the real thing and not liberty caps you will get high) As the former fellow wrote I wouldn't mix with a bunch of people who you don't know andare expected to interrelate with... other folks expectations of you when you pretty high are a real drag. Be comfortable, have music you like, and have a designated sober person... I loved shrooms I had to quit taking them as I wanted to be high 24/7 and that is not realistic.
Mushrooms can take you to allot of places, use them wisely. Google your answer as to how long it's in your system , there are too many variables and I don't want to guess.
As far as the price-- well are they dried, wet, cubensis, Safeway Brown, Liberty Caps ??? If you and 3 buddies get of on a good trip, I would say you got your $35 worth.