The street dealers are amsterdams most popular con, there is practically no chance of getting anything on the street. A nightclub is you best bet for pills and a local for anything else you might be looking for.
last time i was there a Nigerian street dealer trying to sell us pills actually had a test kit (well, apparently a test kit but not one id see/heard of), offered a free sample and his phone number. thats a lot to go through for the few euros he was asking, so who knows he may have been one of the very few honest street dealers out there.
But, on a whole, the street dealers are pushy, thieving cunts. Don't talk to them, I made that mistake in my early visits to 'dam, when you hear someone say something as you walk past you tend to stop and say 'what?' I had some dude follow me for almost a mile trying to sell me coke.
Quite funny actually, started at 40 a g, then 20, then 10, until he was at 5 euros a g!! still, expensive for talc.powder.
I felt sorry for the guy and gave him some change, like 6-7 euros and he started hassling me for some 'paper euro' in his words! cheeky cunt.
The dampkring on haarlemmerstraat is one of my favs for their weed, their diesel and super silver are excellent. Go to lost in amsterdam or abraxas for a cosy place to chill though, as a lot of places opt for uncomfy chairs and loud shitty music. I assume its to stop people falling asleep

Also, if you find yourself near oosterpark hit up smoke palace, amazing cheese haze and chocolope and because its not really touristy its not over priced!
around 8-11 euros a gram and quality was right up there.