Questions before I buy a used Wii U

[BomberBob]

I'm looking at a 3DS for Super Smash Bros. but then the cogs in my brain started turning & I thought about a Wii U instead. If my brother has a Wii U, can't I buy one used for myself & use his GamePad to set mine up? I'm looking to buy it without the Pad to reduce the cost. 90% of my time using the Wii U will be spent playing Super Smash Bros.

Is it possible? Can I use just a Wiimote & Nunchuck with it? Does it have to have Pad paired to it?

Thanks much everyone!