Leveling blocks

CheshireCBR

ok so I am new to caravaning and came accross a bit of an issue on my last years holiday, of leveling the caravan side by side, only to be told I should carry some leveling blocks, now onto the question, A) where is the best place to purchase such things,
and how hard are they to use on your own?

the reason for having to use them on my own is I only ever go away with my 11 year old daughter, and as with most kids of that age its a bit hard for her to drive the car lol