According to Department of Health info, there are no documented cases of HIV being contracted through tattoos. Hep B was the greatest risk, while there have been a couple of Hep C cases reported.
Think I'd advise avoiding amateurs with needles, anyhoo. The incidence of Hep C transmission is likely higher than you realize. Spend a little more time in the ER and you'll see quite the gallery of dreadful art on naked patients...skulls and sexual "art", gang tattoos--ick.
Letting some dingaling loose on you with needles that might be dirty, in order to create a lifelong mutilation? *Definitely* a lowrent behavior.