A bit of context. I am currently stoney broke (really, really broke) scraping together money to keep DD1 at university. I work as a carer during the week but its just not enough. I'm a keen gardener so I came up with an idea of casual gardening business (lawn mowing, hedges etc) to bring in a bit of money.
My friend of 30 years has just taken on a landscape gardening job and offered to pay me £15 per hour digging, moving rock, and a bit of wood cutting etc. I did 3 days solid, my body was sore and aching to the point of hardly being able to move, hands blistered etc. The whole experience was pretty stressful as I have come to the conclusion he is an extremely lazy, disorganised person. He then tells me he won't be able to pay me until the job is done as he is broke and funding the job on his maxed out credit cards (he even asked me to buy some equipment from wickes though I said no thank goodness). I advised him to get a deposit from the customer in order to pay some of the expenses. He asked and she agreed but nothing has come a week later.
So I asked him today what time he needs me tomorrow as I was hoping to get the job done so I can get paid. He tells me a time...then an hour later he tells me not to bother as he feels like the day off and has booked into a fancy restaurant with his family (he's supposed to be skint!). I asked him how long it will be until the job is finished and he said the customer is in no rush and will be happy if it takes until next spring.
I really need some money now and don't want to wait until spring to get my money. I feel I have been completely manipulated into free labour. I texted him and told him that I am not happy and he has taken advantage of me knowing he couldn't pay me. He has now gone very quiet and ignoring my messages.
I am close to tears as I know that its the end of our friendship and feel an idiot for allowing it to happen. He has had a history of taking advantage of me financially (in much smaller ways that I let slide) so I should have known better but I was desperate. 
Thank you for letting me rant!