Getpinz and the needle beast are as legit as it gets, been around a while.
I use 18guages to draw out with into 3cc syringes, then switch to a 25guage to do the inject.
So just get a bunch of 3cc syringes without the needles and a bunch of 18 and 25 guages. You can use 23 guage to inject as well, 25 works fine for me.
1.5" should be good for glute injections if you are just starting out since you probably have a decent amount of bodyfat there. 1" can be used for delt/arm/quad/pec injections.