HBAR - Stay away from Tiger Direct, never had much good luck from them.

Internet - If you can go wired then go wired. The only reason wireless is better is for locations were wired is impossible, impractical or you want freedom of movement. Knowing your setup at your house, go wired. A 5 Port Switch will serve you just fine.
Hardware - Again get the best you can with what you have. I have always had great luck with Dell machines. It's all I ever used till I went to Apple. For you and your Logistics, Amazon Prime is a good bet or take Wulf up on his offer. I may have two Dell Desktop CPU's I could give you. They need some work, just a reinstall of the Operating System and drivers. If someone is will to do the reinstall for you, you can have the machines.

Question, what online school are they using? The teacher in me is curious.