i just glanced at some of the posts that you had on Main Health. Hang in there - you'll get it! i never even saw a size on the lancets i used. there was just one box available to go with that particular device.
have you gotten advice on treats yet? i used to boil chicken breasts, cut them in tiny pieces (1/2" cubes), freeze most of it and keep enough for a couple of days in the fridge. then give one tiny piece after each poke session.
and a heads-up - it can be hard to get blood when you test for the first couple of weeks. there are tricks to help, but it takes a bit for the blood vessels to grow. testing stimulates the growth, so even if you don't get blood, it's not in vain. this is a disease that makes us all develop patience.
it gets easier - really. we'll help you with every step, so just keep asking questions.