Since the discontinuation of all roll and pack film, and Polaroid Originals resurrecting integral film, your camera choices have shifted to Polaroid's newer cameras. Foldable SX-70 cameras are very fine cameras, but require a flash source indoors. 600 series cameras are the most common cameras, and they usually have built in flashes, and a wider variety of instant film. Note that Spectra film is no longer produced so Spectra cameras aren't viable anymore.
Now, technically at this time (2020), you may be able to still order 100 series pack film from One Instant. And if you're willing to pay $15/picture or to try finding expired pack film at $60+ per pack, then you must be serious to use pack film. In that case, you would also need a serious camera. I would think anything less than a model 180 or 195 would be wasting the film. Better yet would be a medium format camera with a Polaroid back, which would give you options with your lens choice.
If you are intent on taking instant photos, consider Fuji Instax cameras. Personally, I don't like their mini format, but they do make a square format similar to Polaroid 600 and a wide format similar to Spectra. Fuji still makes film for this camera as of 2020 at a reasonable cost.