As you well know, in order to increase your skills to ch11 and 12 you need those neat little books that cost a lot of money: the lost books (for ch11) and disappeared tomes (for ch12). There are some things to take into consideration before jumping headfirst into buying books, however.
First of all, there are skills that don't level beyond ch10 0% but the books still drop and are as of yet useless:
- external wounds heal
- internal wounds heal- nukers' FD slow nuke
Second role skills don't level beyond ch10 0% as well (with the exception of the hybrid's scale buff), but at least there are no books for those skills either, so you won't be tricked into buying them.
Then, there are books for "regular" nukes and smashes. Don't buy those either, they are all available in the clan base and you also need to hit second role (and sometimes attain several levels into the ECs or FCs) to use them. Throw in some pieces of steel as contribution and you'll get them cheaper than a player might try to scam you into believing you'll have to pay.
Finally, we have the rest of the heals, the buffs and self-buffs and the shields. Those have level requirements, but as soon as you are able to level them to cheng 10, you can also get them to 11 or 12 as soon as you can get your hands on the books. Some of those are more expensive than others. A short heal will normally cost you more than a warrior's buff that makes the mobs turn aggro, though I did see some weeeeeird prices out there (like 30 kk for a rezz book, as if healers and hybs go around rezzing themselves all day long).
If you have some books on your hand and do not know what they do, you can check the table below (click for the large image)