Wonder Woman, in a word, is timeless. The character recently celebrated 75 years of being in the pop culture forefront, and finally has her own solo movie on the way. Wonder Woman debuted in All Star Comics #8, which has recently seen a surge in popularity. According to the Overstreet Price Guide, a good copy is $11,000, while a near mint copy should be $175,000. So right off the bat, you know these books are going to cost you money. There is currently an ASC #8 for sale on ebay, CGC 4.0 that's listed at $59,500.00 or best offer. Guide on this grade is $22,000. According to GPA a 9.0 sold for $411.01 in April of 2016. Meanwhile, a 1.0 sold for $19,500 in 2016. So even if you're looking for a cheap copy, you'll still be forking over a good sum of cash.
Sensation Comics #1 is also a priority for all Wonder Woman fans, as it is her first cover appearance, her second comic book appearance, and we see the invisible jet for the first time. GPA prices on this book don't exactly line up Overstreet prices though. For example, an 8.0 is listed as being worth around $30,000. But according to GPA, there are two 8.0's that both sold for under $19,000 this year alone. A 7.5 went for $8,890, but according to Overstreet, it should be above the $15,000 mark. You can still pick a solid mid grade copy of this book up for only a few thousand. I predict this book will go up in value the closer we get to the Wonder Woman movie, but I still think this will be an attainable key for many fans.
We all know Wonder Woman isn't complete with he magic lasso, which appeared in Sensation Comics #6. Guide has this book listed for fairly cheap, with $4,000 being the price for a 9.0. A raw copy in what appears to be good shape (2.0) sold for $1,600 on April 5th. According to GPA, a 4.0 sold September of 2016 for $5,655. This comic is going up in value, so it may behoove collectors to act fast on this book.
Wonder Woman finally got her own book in the summer of 1942, with Wonder Woman #1. This book is hot right now. A 9.0 sold for $291,100 in December of 2016. Overstreet has it listed at $60,000. To say this book has shot up in value is an understatement. A 5.0 sold for $40,500 in December of 2016. To give you a better idea, a similar book $8,066 in 2014. A 1.8 sold for $15,000 October of 2016. All Star Comics #12, when Wonder Woman joins the Justice Society, is still a reasonable key to grab. A 4.5 sold for $650 March of this year, while a 3.5 went for $513.
Wonder Woman #98 has also spiked in popularity. A 6.5 sold for $800 in 2014, and then jumped to $4,856 in 2016. Overstreet has it for around $700. A 5.0 sold for $3,300. But be aware that this book does fluctuate in value. It's likely that this book will continue to go up due to the movie, but prices will likely cool later this year.
I realize I have omitted a few first appearances for her villains, but to me these books make up who Wonder Woman is to me. At least from a collectors point of view. If you haven't started investing or collecting in early Wonder Woman books, I think it would be wise to do so.