I think this is a GREAT idea and I'm SO buying one!
I've been through the booster seat phase twice with my eldest two and my youngest is getting to that age where a booster seat is all he needs now.
He's not in my car all the time and I'm not one for having a lot of kid paraphernalia hanging around in it; having car seats and booster seats rattling around in my boot drives me insane.
So HOW fantastic to have an inflatable booster seat instead; blow it up when you need it, deflate it when you don't and bung it in the glove box or a door pocket; absolute genius in my opinion.
It would also be ideal for the grandparents to keep, just in case they ever need to collect your child from school (or wherever) and your car seat isn't to hand. OR for taking on holiday and using whenever a higher kiddy vantage point is required.
I'm rather smitten with this inflatable booster seat, can you tell?! And so are others, the reviews are rather grand.
This ISN'T an Amazon 'Deal of the Week' so the price may inflate (or deflate, of course - do you see what I did there?!) depending on how Amazon feel at any given moment; I'm grabbing one now.
Happy inflatable boosting!