The no-nonsense steel gate that's been in millions of doorways for a reason: cheap, sturdy, and up in minutes.
When you need a second (or third) gate and don't want to think hard about it, the Regalo Easy Step is the reliable default. It's all-steel, tensions firmly in standard doorways, and the walk-through door with a pressure handle is easy for grown-ups to operate. The trade-off is a taller bottom bar you'll step over and a latch that's more basic than premium gates. Don't put it at the top of stairs, and if you love a self-closing door you'll want to spend up for the Cumbor.