* Amazon
* eBay
* Etsy
* HalloweenCostumes.com
* PartyCity.com
* Thrift stores and vintage shops: Thrift stores and vintage shops may sometimes carry ABBA costumes or pieces that can be used to create an ABBA costume.
* Costume shops: Costume shops may rent or sell ABBA costumes. It's a good idea to call ahead to make sure they have what you're looking for.
* Make your own: If you're feeling crafty, you can also make your own ABBA costume. There are many tutorials available online and in books.