We don't have family around to help, never have so we've always thrown money at it. However, we are forutnate in that where we are, there is plenty of choice of holiday clubs, DC's school have one, as does neighbouring school plus a specific childcare company who run club sessions out of several neighbouring schools. There is also Forest schools, sports clubs, gymnastics clubs etc, all with 8/8.30-6/6.30pm schedules. Like another poster, we have the luxury of mixing it up a bit so that the DC don't get bored at the same setting.
Cost wise, it's relative. Compared to nursery fees, they are far less of a strain on pockets! We bank childcare vouchers throughout the year to cover them. Some of the activities give early booking discounts if you book several months in advance. Can mean the difference between paying £30 a day and £25 a day sometimes.
Lastly, we take it in turns with our leave, DH gets a decent chunk of leave, as do I luckily so this year, it's been 2 weeks at holiday club and camp, 1 week family holiday, 1 week of DH at home, 2 weeks of me at home. We alternate for half terms and Xmas too.
It's all the random mid-morning and early afternoon invitations to schools, special assemblies, sports days etc that we find harder to accommodate. Having said that our school is better than most from what I can see. The head actively tries to accommodate the needs of working parents so for important things like plays, they try and do two three performances thereby increasing the chances of being able to attend at least one.
It's a juggling act though, but you get used to it and it becomes normal after a while. Have to say I am dreading the point when DD1 is too old for camp/holiday clubs but too young to be left alone! I remember being in charge of my younger sisters from age 12/13 when my parents went to work but this no longer the done thing....