Your options are...
- THC oil - which I find a bit hit and miss due to the amount of time you need to let it sit under your tongue
- gummies - which I prefer as you can better control the dose. There's plenty of imported gummies from CA here. For a first timer, 20mg of THC should be sufficient to help you sleep. So it should be fairly inexpensive. It does take an hour or so to properly hit you, more if you take on a full stomach
- smoke/vape - which is the fastest way to get the effect. When you buy the weed, make sure you get Indica and not Sativa as Sative can keep you awake, whereas Indica will have you nodding off nicely. If you can't get a pure Indica strain then get a hybrid that is 80/20 Indica/Sativa.