I go to my local needle exchange place to get all my bits and pieces, first time i went i asked for the different pins barrells etc, and i was told they have a premade steroid kit, comes with 10 of everything, pins are 21g and 23g, i was using the 23g for a while and i have just switched to the 25g. i ask for the steroid kit plus X amount of 25g. I normally give the sharps container back as i dont require it.
To find one in your area just google needle exchange program and the city you are in.
the only sketchy part about it is when you run into a junkie haha. i normally let them go first as they need it much more than i do.