Decriminalization And Undercovers

So my state is decriminalized, nothing but a ticket if caught with up to like an ounce I think.
 
I had 2 dealers - one got out the game as she's graduating college and moving on and the other moved to Colorado. Within days of each other. Right as I was running out and my cash flow wasn't at a point for buying because of a recent big purchase I made. 
 
Anyhow, hearing stories about people finding dealers on craigslist I went to scope it out and it was littered with caregivers selling to people with cards, but I found one regular dealer. Messaged him and like his prices and strains and he was only offering 3.5, 7, 14g.
 
I figure there is a high likelihood its not a cop because they're not trying to push an ounce which is odd because thats where you could start looking at time or at least probation and a record. 
 
I likely have a good, successful future in front of me and I don't want to ruin it.
What I am asking mostly is:

Where decriminalized, is it just for possession or also purchase? Like if it was a UC could I be seeing anything more than a ticket/lost money/no weed if I bought a quarter?

 

Yea I figure as much. Like I said, I likely have a real good future in front of me and its not something I want to screw up. I genuinely use cannabis for medical reasons (I have intermittent explosive disorder - self diagnosed but 0% doubt in my mind) but I dont see doctors so when I tried to get a card I had no medical history to fall back on. 
 
Just wanted to get some secondary opinions or see if anyone actually knew how it worked from the legal side of things. 

 

success