Every Friday payday, 

I stack sats first,keep on side for my bills and rent,

 then I'm left out for £100 for a week, to split for:
£ 40 transport
£ 20 lunch or delivery
£ 40 supermarket
£ 30 cigarettes
£ 30 weed
£ 20 beers
£ 100 diner with wife

 makes u, a math expert!