Well Bot's are like water..
If you live in Paris you buy water in bottles [Pay] and don't drink the water from the waterTap [Free] but you can do it , but you prefer the water in bottles ;)
If you use Free bots , you can't do something on the same time , exepted if you configure a VirtualBox , but if you want to do something during the same time , well you have to get the Background Bot...
Suddenly , now personally i would use the Free Bots , because since the Bot-Kill that SF did while changing their Scripts or Idk what , Bots in Background are very hard to code...
The work is worth.
But
I personally prefer use Virtual Box & The Free Bot's because i know how to set them up..
Greetings,
Toski