It's fine if a laptop doesn't have a builtin optical drive. It's more important to have USB drives ready for use, but that's a separate thing entirely. I wouldn't buy at Walmart because they simply aren't trustworthy enough when it comes to returns. It's much safer to go with Amazon or Newegg.
As for HPs, you buy what you get. The last time I remember that HP made a good product was HP-UX (an operating system), though that was in the late 1990's. I can say the same thing about desktop computers in the mid to late 1990's. The rest? It's worthless junky plastic that'll break. The moment your kid gets frustrated and presses a key too hard is the moment it'll break and your wallet will scream. You'd be doing yourself a favor by spending a bit more money on something of a higher quality. Consider it an early birthday and "winter holiday or something" present. If it already is both of those, simply use up their next birthday/"holiday or something" present. Or, you can use this as a lesson for them when it comes to good spending habits by asking them if they're willing to give up their next birthday/"holiday or something" present in exchange for a better laptop -- call it an IOU (i.e., "I (the kid) owe it to you and promise not to nag you about my next birthday/'holiday or something' present because I'm getting something super cool this year").