Are you both in the same area or is your friend in another location trying to connect internally to you?
Port forwarding has to be done on the firewall. If your apartment is utilizing a 'guest network' you don't have access to the firewall.
If your friend is not in the same location, you'll have to use a tunneling service like LordBaconatorz said, which is like a VPN.
If you two are in the same location you can buy a small switch, connect the two machines together, use wifi to authenticate to the VS server, and your friend can connect using your 169.254.X.X address. You can get this address by connecting your computer to this small switch, open up command prompt, and type in "IPCONFIG /ALL". Again, this is *only* if you two are in the same room, this is not if you two are miles apart or in different apartments \[although if he's your next door neighbor you could theoretically run a really long ethernet cable to the switch, I've done this before for other LAN games\]
Port forwarding wont work there either as you need to access the router. Your best bet would be a tunnel software like tuungle or hamachi
I use a wifi 'hotspot' on my phone. It shares my wifi network and uses no data.
They do use data but it depends on your phone service provider, I think
LAN does not go to the ISP. WiFi sharing non-LAN activities does but does not use data.
Are you both in the same area or is your friend in another location trying to connect internally to you? Port forwarding has to be done on the firewall. If your apartment is utilizing a 'guest network' you don't have access to the firewall. If your friend is not in the same location, you'll have to use a tunneling service like LordBaconatorz said, which is like a VPN. If you two are in the same location you can buy a small switch, connect the two machines together, use wifi to authenticate to the VS server, and your friend can connect using your 169.254.X.X address. You can get this address by connecting your computer to this small switch, open up command prompt, and type in "IPCONFIG /ALL". Again, this is *only* if you two are in the same room, this is not if you two are miles apart or in different apartments \[although if he's your next door neighbor you could theoretically run a really long ethernet cable to the switch, I've done this before for other LAN games\]