From Utopia for Realists.

2009 in London 13 homeless men were given £3,000 a month with no strings attached. After 18 months 9 of them were off the streets. It cost £50,000 a year including salaries of social workers.

The 13 men cost an estimated £400,000 per year in police time, court appearances, social worker support. So while the overall yearly cost was around £30,000 per homeless man before the experiment, that was £30,000 for nothing, no result, no improvement, as these men had been homeless for many years. For only £36,000 of 'free' money, 9 people fixed up their lives and got out of homelessness. 9/13 is a lot better than 0/13. Presumably there is long term savings as those men get back onto their feet vs £30,000 per year in social services costs with a low rate of improvement.