It is very difficult to say whether 200 MB is enough or not, because it depends on how much data your application keeps in memory.
There are various settings in IIS ... For example,
1) If POOL size limit is reached, you can shutdown the application ...
2) If Pool size limit is reached, you can recycle your application pool ...
3) You can reset your application with the new worker processes ...
4) CPU limit settings ... and so on ...
So, it all depends on settings of your application pool by your hosting provider ...
To avoid all these, what you can do is, 1) Ask your hosting provider to give you remote accesss to manage IIS properties of your websites ... If you have remote access, you can adjust various settings based on your needs ... 2) If you have a budget of roughly $20 a month, Go for a virtual private server hosting ... where you have full liberty to set everything for your IIS.