Instead of vacuum cleaner, I suggest you to buy mats which are breeze to clean and save car's original carpet like Star/kagu 3D mats. No way dust/sand will settle on car's carpet then, these mats are also very easy to clean.
Trust me you will get bored/tired of vacuum cleaner. Buy these mats and avoid all hassles.
I have COIDO Vaccum cleaner which works on mobile charging port.I always place it under driver seat .The wire is long enough to clean the boot too. It achieves 90 % results without body gymnastic skills and 95 % with gymnastic skills.
Only drawback is unavailability of blower which makes difficult to clean few crevices where its suction nozzle can not reach.
It is also provided with soft nozzle to clean seat covers.
There is a drawer at bottom which is meant for storage of wire, but I do not use it
IIRC, cost me approx Rs 2000.