HIV doesn't discriminate between the substances that are being injected - steroid users and heroin users share the same level of risk. Sharing injecting equipment may take place by accident - being stuck by a discarded needle for example. Any situation where body fluids can be exchanged carries risk - wiping up a spill of any body fluids should not be attempted without adequate protection. From an infected mother to her baby. People who are carrying HIV infection can look and feel healthy - they may not be aware of the infection themselves.
Condoms are available free from family planning clinics.
If you use drugs and are injecting, always use a clean set of equipment. Remember, HIV and other infections can be passed on if you share any injecting equipment. Use good judgement. If you use drugs or alcohol, your judgement may be affected - you may be more likely to engage sexually with another person or may decide that you don't need to use a condom.