Even the onboard NIC on your motherboard will work, unless your friend has some older PC or cheap mobo without one.
I've never had any particular problem with Realtek Ethernet chips. For instance, this one is my backup NIC. It's the "Extreme Edition" where the chipset gets a heatsink! (That's the PCI version; the PCI Express version costs twice as much.)
Or you could pay twice as much for an Intel card, or ten times as much for the overrated Killer NIC, which heatsink is ten times larger.