1. I've NEVER smoked before so I just want to know how much I should plan to spend on weed down there. I know you buy per gram and that it cost about 5 to 10 Euros / gram. But how many grams do I need to smoke to get high?
2. What do you get when you buy the weed? So I get a gram of something but how do I roll it? And with what? Do I buy cigarettes and mix it with that or what?
M8 if you buy a gram of some good gear and you have never smoked B4 that will last you a few spliffs.
You buy a gram of weed and get given a small quantity of gear in a bag. Stick to the better known shops so you can get decent gear (No fear of being ripped off). You can either roll it pure or smoke it with some tobacco in it. If you dont smoke tobacco the dont start just smoke it pure. You dont have to smoke the joint in one go that way and can smoke as and when required.
You should be able to get pre rolled pure spliffs in most Cs so you could give them a try or some space cake if you cant roll.
Enjoy
I would avoid the space cakes for first timers, as it is quite difficult to regulate the right dosis, and these things can really knock you off.
Better go for a pre-rolled. There are even some CSs which roll it for you if you ask them kindly and leave a tip. At least you know what you smoke then.
As the above said or alternatively get yourself a pipe from one of the many headshops in dam for roughly 5e and just toke away on that, no rolling required,good times,high times
Oh and by the way a gram should be more than enough to get a first timer high.Another question you might want to consider is what type of high you want,for example if u want a chilled relaxed high that sort of glue's you to your seat get a indica dominant strain,or if your after a more clear head high that wont get you too tired stick with the sativa strains EG.anything with haze in it usually does the trick.hope this helps.
Do you smoke tobacco? If you do, then maybe you want to smoke a mixed joint. I'm not one to promote tobacco use, but if that's what your used to, then it might be a good start for you. Also, maybe you want to practice rolling before you go with some cheap tobacco. I've never bought pre-rolled joints before, so I can't tell you where the best deals are, but you could opt for that. Most are mixed with tobacco however.
I'd start with a light weed, ask the budtender. If the budtender isn't too keen on advice, find another shop that feels comfortable to you. If you're traveling solo, maybe you can share some smoke and tips from fellow smokers in the coffeeshop. Have fun.
A gram will get a first-time smoker high several times. For a first-time smoker to go through two grams a day of Amsterdam-quality bud would be quite a challenge.
Any head shop in Amsterdam will have cylindrical rolling machines for sale for about five euros. Buy one. Be sure you get a cylindrical machine, not a conical machine (cone-shaped joints are the European method, but the cone-shaped rolling machines don't work as well, in my opinion). Insert the smoking product, insert the paper, roll, lick, roll. Presto, you have a cylindrical joint, shaped just like a cigarette.
If you want a cardboard tip (the tradition in Europe), just put the rolled-up tip at one end, fill the rest of the rolling machine with the smoking product, and you'll have a tipped joint.
Buy your own grams. Roll your own joints (you're never sure exactly what's in there with pre-rolls). Papers are available, for free, in any coffeeshop (or for sale everywhere you look). So are tips and grinders (a product used to grind the bud before smoking). The only thing you need to bring to a coffeeshop to ensure professional-quality joints the very first time is a rolling machine and enough cash to buy a gram.
When you do know then just let FbN know and you can hook up with a meet 'n greet if there's one happening or create one if there isn't, you'll then get all the help and advice (and then some ) that you could wish for.
May I wish you all the best toking I could wish for myself however, whatever you do and however you do it (joint, pipe, vap, bong, cake) enjoy and have fun bom Shiva
) that you could wish for. 
however, whatever you do and however you do it (joint, pipe, vap, bong, cake) enjoy 
