I personally grant characters sets of consumable magic items appropriate to their class and level - aside from the funds that they would get. This is done specifically to address and moderate the consumable nature of items that would have been bought/found/consumed or otherwise used during the time frame prior to the character beginning actual play. Not perfect, but works for us. Now if a wizard needed additional spell choices for a spellbook (beyond the freebies), they could sell these or use the funds that are included for their level at creation... but basically they have to spend.
Another method that I have used in the past to moderate the spellbook & consumable magical items that were assumed to be acquired over time, is to simply grant spellbooks a base set of spells (beyond the freebies) equivalent to the spells/day that the character gets (no bonus spells for high scores though)... for instance a 5th level wizard would get 4 free zero level spells (I only grant the PHB ones for 1st level - so these can be chosen from other sources), 3 free first level spells, 2 second level spells, and 1 free third level spell. These spells added to the 2 freebies per level makes a decent spellbook for character creation purposes.