I run a rather high amount but a lot of people run 3-5 megabytes
3 megabytes = 3145728 bytes
4 megabytes = 4194304 bytes
5 megabytes = 5242880 bytes
It all depends on what you can spare
might want to start with
0.5 megabytes = 524288 bytes enough to watch youtube but not so much that warez can be downloaded.