Lore Tokens, as you now know you get for doing tasks for trainers or beeing lucky and get some as loot.

In the beginning it is very slow since you only get a few tokens for you work, which can be very frustrating when you know you need lots of forms.
It does get better as you get higher craft levels since the tasks will give more tokens.

When starting out the best use of your tokens will probably be at the Automatons in Dalimond or New Rachival.
Formulatrons I think they are called (a while since I used them....)
You basically pay 1 token and get a random formula back, which will be appropriate for your level.
Might still get a few you can't scribe immediately, but those you just save until you can scribe them.

Any extras you get, you put up for sale on a consigner for about the price you would have bought it for, since that might actually lead to it beeing sold.
Have seen people putting up Beginner Forms for 500c each and I find that to be about 350-400c too much, at least for someone just starting out their career in Istaria, but that is what I think of the matter...

And of course, you should take a look at the consigners as well and see if you find any needed forms for a decent coin.

For your question about wether people sell Lore Tokens or not:
Yes some do, but the price will most likely be a tad high (at least from my experiences on Unity), so you might want to grind away at the tasks anyway, and visit the consigners from time to time to look for some decent bargains.

I don't think things will change so that you can buy all kind of formulas from trainers with money, but there are some trainers that only accept money for forms.
Fashion Designers (social clothing) and Construction trainers (Mason, Carpenter and so on) comes to mind.