Well, there is no "basic green tea", there are many different variants which are all quite different. Start by comparing a solid Chinese tea (eg. longjing) with a Japanese one (eg. sencha), brew them exactly as instructed (Japanese tea in particular turns bitter and soupy if you let it steep too long), see which one you like more and go from there. And instead of fancy tea stores, go to an Asian grocery and pick up any random mid-priced package.

https://en.wikipedia.org/wiki/Green_tea#Green_tea_by_country