I have tried to search on this board and haven't seen anything on point. I would like to know where is the best place to purchase spells. I'm not to far into the game, but haven't come across to many places that appear to have a good selection of mage spells to purchase. Both BGI and Icewind Dale had places where decent spells could be purchased. Any help would be appreciated.

There are 3 places om Waukeen'e Promenade
1)Ribald - has a few, none are especially great
2)Lady in the back upstairs of Ribald's Place - she's good, she should be in between 2 bookshelves in the top left corner
3)Galoomp the Bookkeeper - One of the Merchants above the Den of the Seven Vales (the place where you fight Mencar Pebblecrusher and his gang)

welcome to IW.and there are merchents on the street who have them.like in the first area there is a man north of the inns that sells spells

Spoiler

you will also get a bunch the first time your party gets attacked moving between zones

1. Right now, you can buy better spells in Trademeet but you'll have to solve the Trademeet problem first.
2. Ribald will sell better spells later - in chapter 6.
2. A few of higher level spells are fixed treasures in the game. Most of higher level spells are random treasures. You cannot buy them at all. In the other words, the contents of your spellbook is always a matter of a random roll. Completely wrong? Sure. Use CLUA Console.

And when and if you get to ToB, Lazus Libratus(?) has lots of good spell scrolls!

<font color="gold">Lazarus Librarus. ;) </font>

There are a few important spells, like Greater Malison, Lower Resistance, and Breach, that aren't sold in any convenient store, and must be found through adventuring (most of those spells can always be found in certain locations), so you'll probably want to have your PC already have those spells in his book when you start out.

There are even a couple of spells (I know of at least one--Spook) that I can never find in the game AT ALL, so the only way to ever cast them is to pick them at the start.