[RPG] How to determine the value of spellbooks placed as treasure

My group has just simply (for the sake of simplicity) just reduced whatever objects we find that have value to their gold value. This reduces book keeping and simplifies wealth in 4e.

However, if you want to pedantic, or show that an item is far more significant than a run of the mill gem stone there are skills in 4e that can be used for appraisal. In the Trade Goods entry in the compendium there is a section called "Buying and Selling:"

To perform either of these transactions, establish the total value of the trade goods in question. Use the major purchase column on the table in the Pocket Change entry to figure out the level of this transaction. For example, unloading a rare book worth 10,000 gp—or a forged copy of the same—would be a 15th-level transaction. Use this information with the Difficulty Class by Level table (Rules Compendium, page 126) to determine the DC to sell or buy a trade good, or to recognize or pass off a fake item.

Then make a check (usually Streetwise) to find either a buyer or a seller. Use the moderate DC for the level of the transaction in a location with a good-sized marketplace or population. Use the easy DC in major trading hubs such as the City of Brass, and the hard DC if the value of the items far exceeds the locals’ wealth. A successful check indicates that the transaction has been completed.

This is followed by a table with the prices of common items. Again, I would only use these rules occasionally, adventurers should have an idea of what the loot they find is worth, and its probably worth letting them just convert it to gold (As that is the point anyways).

So in short: Yes. Unless you want to show significance to a specific item.

Note: The RAW approach here would involve granting the players a Pouch of Platinum or similar which would allow them to automatically change gems into coins.

Spells On Levelup

You get those spells in a spellbook, by RAW:

At each new wizard level, she gains two new spells of any spell level or levels that she can cast (based on her new wizard level) for her spellbook

But, you don't have to put them all in the same book. In fact, a standard spellbook only has 100 pages, and each spell takes a page per spell level. So you'll likely run out of pages and have multiple books, or make the investment in a Blessed Book.

"For her spellbook" implies to me you only get it for free in one book, though it doesn't say so outright (it also doesn't say you get them in 17 books). If you want to make dupliate copies of a spell, there's rules for that:

A wizard can use the procedure for learning a spell to reconstruct a lost spellbook. If she already has a particular spell prepared, she can write it directly into a new book at a cost of 100 gp per page (as noted in Writing a New Spell into a Spellbook, above). The process wipes the prepared spell from her mind, just as casting it would. If she does not have the spell prepared, she can prepare it from a borrowed spellbook and then write it into a new book.

Duplicating an existing spellbook uses the same procedure as replacing it, but the task is much easier. The time requirement and cost per page are halved.

Does a spellbook have to be a book?

A spellbook is an actual item in the item list, and is mentioned numerous times specifically. You could interpret that to mean it has to be a book.

That said, Complete Arcane has rules for differing types of books. A book made of something else is still a book, and the cost of copying the spells is the same unless CArc says otherwise. For something like bone fragments, it doesn't: the extra cost is in buying a book made of that material.

So yes, in that case your free spells could go into anything that counts as a spellbook in that way. On something else, it becomes undefined and is up to your DM.