Yes, I worked with some burd who basically lived on Credit Cards by paying what she could afford then transferring the balance to another Card offering interest free transfers and repeating the process - I never found out what happened when she (presumably) ran out of Card providers!
Yes they used to call them / us as I did it myself "Rate Tarts" where you keep moving the money around from 1 low or interest free card to another.
I calculated at one point that I was effectively over spending on average by about £10 a week or £500 a year however in the mid to late 90's I was really struggling financially after being dropped in it by an ex and left paying a joint mortgage by myself.
The mortgage company when I sat in front of them and said I wanted to keep the house by myself looked at the loan value and what I earnt which was basically shit (think the equivalent these days of minimum wage) and informed me bluntly that I couldn't afford to pay it and if I came to them on my own there was no way they would lend me the money.
They did keep me on however as i'd been making the payments on my own for the previous 6 months
I worked 7 days a week in a shitty job that I hated and got talked to and treated like shit by everyone, I didn't go out socialising for 2 years, I rented a room out in my house and ended up with a couple of good people but also a couple of nightmares who made my life quite difficult
I could have buckled under and looked to get the debt written off or reduced however my debt was for basic living rather than holidays and flash cars and living the high life etc so I didn't see that as an option as I still needed to live
I have to say my situation was pretty dire for a few years and it almost fucking broke my will on a few occasions, safe to say that IMO anyone that racks up debt living the high life then walks away is basically a cunt

In the case of the OP I don't know his circumstances therefore i'll not pass judgement on him but I do think he needs to clarify whether he's just skint from loving BMW's too much

Edit - I was so skint at one point when food shopping that i'd only use a basket rather than a trolley as you can't fit so much in, I also had to add up how much value I was putting it the basket so that I didn't have to put anything back when I got to the checkout.
One time I needed washing powder to wash my work shirts at the weekend but it would have bust my budget, can't remember what the choice was between but it was washing powder or some essential like food. I chose the other as I could get washing powder the next week when I got paid at the end of the month, got home and started dismantling the cardboard washing powder box getting small amounts of powder out of all the little recesses under the internal flaps and the corners of the box etc, just got enough for a load of washing

Money isn't an issue for me now however I still add up what i'm putting in the trolley and i'm normally right to within 50p or a quid at the checkout, couple of times it's allowed me to question how much the shop is when it's £10 or £20 more than expected and they've always rung something through twice