Specific static IP settings on different WiFi
I am assuming you're on Windows. If not then please correct. If you go into:
Network and Sharing Centre > Right click Wireless adapter > Properties > Select IPv4 > Properties.
In there configure your primary network settings under the general tab (probably obtain IP automatically) and under Alternative specify the information related to your other network.
Hope this helps
EDIT: So using alternative IP. Generally speaking you would configure your alternative configuration to specify settings when a DHCP server is not present (and cannot collect an IP automatically). If this is the case for you then set the primary to collect an IP automatically (for your school network) and assign manual configuration to alternative when at home.
If, however, this doesn't work you can probably assign both networks manually, but this would depend how your school network runs. I assume you won't be able to specify a manual connection if there are several hundred systems on the network. Be aware though, as pointed out below, once you start specifying static network configurations you won't be able to use your system anywhere else without resetting the network.
Depends on what you mean.
If you mean, can I set myself up with a static IP at all? The answer is yes, always.
If what you mean is: can I set up myself to have always the same IP address, the answer is no: the reason is that you will have different subnets in different places. You have 192.168.1.0/24 at home, but 172.168.1.0/24 at school. Next time you go to an Internet cafè, you may find a subnet 192.168.0.0/24, or 10.10.0.0, and so on. Having the same IP address on these different subnets makes it impossible to use them, since the number you chose for yourself, 192.168.1.50, belongs to your home subnet but does not belong to any other subnet mentioned above.
This is the reason why most people do not use static IPs on wifi; the most common use for static IPs is in devices which cannot be moved, so they belong by definition always to the same network: dekstops, servers, routers, printers, TVs, and so on.
It depends on your router/ap if it supports this for not, but you should be able to DHCP reservation using the MAC address for your wireless card and assigning it an IP (192.168.1.50 in this case).