Now a days, every phones have 3MB ram and 16 GB storeage. If you are using old or low cost phones its ram and storage space is very less.You cannot install new apps and update apps. Then, you can find some difficulties in usages.
You will get lots of android Apps under 1 MB. These apps are helping you to speed up certain extent.
The following apps very useful and its size is under 1 MB.
This is a lite browser.
Vanilla Music is a cleana and simple music player it supports common files formats.
This app that secretly takes a photo using the front camera when someone tries to unlock your phone with the wrong code.
It provide you graphical representation of storage.
It helps you to uninstall app quickly and easily.
More Details watch this video.