If you desperately feel the need to read a spell book I suggest you go for the historical side and err on the side of the tried and true by this I mean something like the charms in the Carmina Gadelica or one of the series of books put out on Kindle by a publishing house called Albacraft. The paperbacks are around $21.00 and the Kindle versions are $1.59 which is a much better price break.
I still would never use these but you can get a better feel how spells were tradtionally used by the Gaels. There are many books in the series that contain folklore and stories that were collected from the people that used them everyday.
I use Amazon Recommends to see what, if anything tickles my fancy to read and I bought a book that seems to have triggered the addition of a lot of spell books be added to my list. A cursory examination will show that most are done merely to sell a book.
I have a prejudice. I don’t believe in spell books. Any witch, pagan, etc with half a brain should be creating their own spell books and not using anyone else’s book. If you can’t write your own spell, you have no business being a witch.
To write a good spell all you need is clear intent and focus. You decide what herb if any or candle colour, if any you use. It doesn’t need to rhyme. It doesn’t have to be a yard long but I do think you need to write it down if for no other reason that it will clarify your intent and to make sure you are not casting in the heat of anger when some other remedy would be more efficacious.
When you use someone else’s spell you really have no idea why and how it was written. You don’t know the original intent for the creation of the spell. It really isn’t that much different than using a Ouija board which I also think is pretty stupid.
To create a spell you need very little. Intent, focus and release. You have to remember to release the spell/energy to set it into motion. Another reason to not be angry when you work a spell. You could be so mad you hang on to it instead of releasing it.
The only reason I can think of for writing a spell book is to make money. If you can’t do it yourself, you aren’t trying hard enough. Buy a book of correspondences if you must although I think those are rather personal too but write your own. Don’t use a second hand spell.
Spell books are the Good Will/charity shop of magic.