There are no real "basic" herbs, it is all dependant on what you need to use them for.
The best herbal guide book I have ever read is Scott Cunninghams - Encyclopedia of Magical Herbs. But you will have to splurge on a book.
Alternatively there is a herb section on this site that has and A-Z of the most common herbs in magickal practice and see if there is anything that particularly draws you to it.
Personally I use a lot of:
Sage, Marjoram, Lavender, Chamomile, Rose, Juniper, etc. But everyone is different.