A spellbook from a wizard has many uses if you got a Mnemonic Vestment:
If the wearer is a spontaneous caster, once per day she may use a spell slot to cast a spell from a written source (such as a scroll or spellbook) as if she knew that spell. The spell must be on her spell list, the same spell level or lower than the expended spell slot, and the same type of spell (arcane or divine) as the spell slot expended. The caster must also understand the written source (such as using Spellcraft or read magic) and be carrying it. Activating the robe is not an action, but casting the spell otherwise works as normal, including casting time, providing components or foci, and so on. Using a mnemonic vestment’s properties does not consume the written source.
So yeah, grab one of those and enjoy your vastly expanded spell list (once per day, at least). You may also hire a wizard to write more spells into the book, but that can get expensive quickly considering the costs of such services for higher level spells.
A quick last note on that, using such robes when crafting magical items is one way to avoid sorcerer's natural disvantage on it (fewer spells known), which normally results in a -5 to your Spellcraft check per missing required spell. Since the vests are used once per day, you may supply one missing spell per day without any disvantage by simply having a scroll or the spell written on a spellbook.
So, if you take the vest and the Scribe Scroll feat for instance, you could write scrolls for all the spells in the book, which not only sell for more than selling each spell individually in the book, but would also give you a few extra tools to work with during your adventures.
Similarly, the Versatile Spontaneity feat allows you to do the same, but it takes a spell slot 1 higher than normal (Ex: a 2nd level slot to cast Magic Missiles):
When you regain spell slots at the start of the day, you may opt to prepare one spell you don’t know in place of a daily spell slot 1 level higher than the prepared spell’s level. To do so, you must have access to the selected spell on a scroll or in a spellbook, and the spell must be on your spell list (even if it is not one of your spells known). This process takes 10 minutes per spell level of the selected spell.
You can cast the selected spell a single time, expending the spell slot as though it were a known spell being cast by you. Preparing a spell in this manner expends a scroll but not a spellbook. A spell prepared in this way is considered its actual level rather than the level of the spell slot expended. You can apply metamagic feats to the spell as normal, as long as the spell’s actual level plus the increases from metamagic feats is 1 level lower than the highest-level spell you can cast. For example, a 12th-level sorcerer with this feat, a scroll of fireball, and the Empower Spell metamagic feat could prepare an empowered fireball spell in her 6th-level spell slot.
You may also borrow the spellbook to another spellcaster (for the same cost as selling the spell), which should earn you more money than selling it, in the long run. But considering the nature of the game (explore dungeons and kill monsters), that is very unlikely to happen, as you would need to spend time looking for potential customers that could need the spells you got in your book.
Cost to scribe spell = (Spell Level)² x 10gp
Time to scribe spell = Spell level in hours