I was in the same boat when I was subbin last year for a builder, it went... work for 4-5wks get paid for 2-3!!! Waiting for stage payments or some other crap... me and the other lads were well pissed off you working all the while earning good cash on paper but you can't get your bloody hands on it!! Best way I reckon is what I generally do, bit of subbin (pays your tax), do some work for couple of property developers (that's gross pay) plus all of your own work on top (that's your cash flow), works a treat, always got money coming in from one or the other.
Cards are ok as long as you get the habit of paying the bloody things back, as the lads said they can screw you!