It's 50gp per spell level to copy a found or traded spell into your spellbook.  in earlier editions, to represent finding, trading for, or buying knowledge of a spell in your backstory, you paid half the cost to transcribe the spell for knowledge of the spell.  By that formula, it would be 75gp instead of 50gp for a 1st level spell.<br/><br/>In every version of 3rd editon. (3, 3.5, and pathfinder) that was explicitly allowed in the DMG.  I don't find that in this edition.  it's backslid to older editions of D&D when it comes to creating characters above first level. (Don't get me wrong.  2nd edition D&D is great, so that's not a bad thing.)<br/><br/><div class="spoiler_container"><div class="spoiler_header" onclick="hideSecond (this);" role="button">Quoted from page 134</div><div class="spoiler_body">Your Spell book<br/>  The spells that you add to your spellbook as you gain levels reflect the arcane research you conduct on your own, as well as intellectual breakthroughs you have had about the nature of the multiverse. You might find other spells during your adventures. You could discover a spell recorded on a scroll in an evil wizard's chest, for example, or in a dusty tome in an ancient library.<br/>  Copying a Spell into the Book. When you find a wizard spell of 1st level or higher, you can add it to your spellbook if it is of a level for which you have spell slots and if you can spare the time to decipher and copy it.<br/>  Copying a spell into your spellbook involves reproducing the basic form of the spell, then deciphering the unique system of notation used by the wizard who wrote it. You must practice the spell until you understand the sounds or gestures required, then transcribe it into your spellbook using your own notation.<br/>  For each level of the spell, the process takes 2 hours and costs 50 gp. The cost represents material components you expend as you experiment with the spell to master it, as well as the fine inks you need to record it. Once you have spent this time and money, you can prepare the spell just like your other spells.</div></div>