Not sure if the original question is taking the piss/trolling but if not my advice is forget it, you say you want to give money to someone who needs help then bung a few quid to a charity helping with addiction or something. Might sound all fluffy here but I don't mind, if a woman is selling her body on the street she needs professional help, it's not their choice is desperation to land the next hit. Addicts are far more likely to be lax with medical check ups, you put yourself in danger of mugging and arrest for soliciting. Like a warm cosy bed myself not a 5 minute blowjob behind a skip with used rubbers and needles everywhere.
There are loads of parlours in Brizzle, loads of indie girls advertising on AW and various other sites, use these, the women will be working as it's their choice to do that line of work and earn fantastic money, not because they are desperate for the next £10 bag of skag.