Hi Wendy,
Welcome to the T-shirt forum.
I would suggest finding a local screen printer and ask them questions. Sounds like you are talking small quantities. If so, ask about
DTG, or if they know anyone that does vinyl transfer. Screen printing will give great results, but small orders may be costly to set up.
DTG (direct to garment) may be a little cheaper to set up, then vinyl or heat transfer paper should be the cheapest. IMO vinyl will hold up better than transfer paper method.
Hope this helps,
Good Luck!