Yes. But it takes one of those stamps to send a regular letter. No matter if the price changes. No conspiracy here. Don't use letter mail postage for parcel mail.
Sure, but all weights require the same number or permanent or forever stamps, regardless of when said stamp was purchased. The value of the stamps are now always base postage, regardless of when said stamp was purchased; hence why they don't place the value on them: it isn't fixed.
In the us I want to say it's nominally 1 (forever) stamp per oz.