Depending on the specific EULA (End User License Agreement), most foundries don’t charge additional fees for font usage on products they design and sell at all. Though in such cases often a MUL (multi-user license) is necessary, since more than 5 designers (also depending on the specific EULA) use the fonts in large companies, this usage itself is usually covered by the basic license. Speaking for FontFont, it’s definitely covered.

If the products are digital, and you require the fonts to be installed either on devices, or accessed interactively online through a server, then you will need a special licence.

I think the P22 restrictions are somewhat unusual (as I recall House Industries has some similar rules), but checking the EULA for each font you intend to use in this way is probably the best plan. As Nick mentions, digital products, along with rubber stamps, and in some cases using dingbats as primary design elements are things to watch.

Specific information about the P22 licensing model regarding packaging and usage beyond the font data can be found here and here.

So strange that P22 can keep going with that. “Yes you can license the fonts, but this and this and that and this and that and this and this is not allowed”. There’s no good way to know how much a license will cost beforehand. Why not reveal the factors and the formula that affects the price tag?