Some do and some do not. It is the preference of the drummer. The thrones(stools) that come with a new kit are usually cheap and do not have a back rest. Gibraltar, Yamaha, Ludwig, etc. make them with backrests,but they are more costly, $150 USD and upwards to about $250 USD.
Take it back to the shop
A drum kit that is very germy.
The Tama drum kit
There is no 'best' drum kit. Each brand and type of kit has its individual advantages.
Usually, a fourth tom is not included in the standard kit.
bass drum
There is no set price its what you want in a drum kit, make, size of kit, accessories etc.
kit
You can find cymbals inside a drum kit. The number of cymbals is different in each drum kit, because there are different kinds of music. But all come with a Hi-hat unless it is only a drum kit with only drums.
No.
The bass drum
the snare drum