I'm now a SAHM (with 21 month old daughter) but worked f/t previously until my older child was 13+. Basically, I paid out a fortune in child care .... had no other choice as son's dad was useless and I was lucky if he managed to organise 1 week off for himself in summer holidays, even though he was self employed. I always used 2 weeks of my annual leave, trying to co-incide with my childminder's own holiday so I didn't have to pay for when he wasn't there (which wasn't always possible) but needed (and more than needed !) the other 3 weeks for Easter, Xmas, half etrms, inset days, ill days etc.
Holiday clubs were useless for me as I had to drop son off at 7.45am latest and could pick him up 6pm earliest. In all those years I never found any sort of care, other than nursery or childminding which came anywher close to the level of care I actually needed. And, in all that time, my retired mum never once offered to help out - even though she looked after my sister's kids one day a week for years ! And not a single other relative / friend ever helped me either.
The only way I could possibly manage the large holiday bills was for me and childminder to work out the total I'd be paying over the year and then divide it by 50, so each week was the same and there were no sudden drops in my usable income. This really only works though once you've established you're happy with the childminder.
Of course, the financial considerations paled into insignificance when compared to the huge guilt I felt at leaving son in childminder's all day - especially as he got a bit older and most of his friends were full of various activities they'd got up to. Unfortunately though, I believed I had no choice but to work at the time, though I was never a high earner and always struggled .... with hindsight, I wonder if I would have been better off working p/t and applying for benefits ?