I recently went down this road in Perth where I live.
A mail-order company called "camerasky" was selling the Nikon B700 for AUD$413 plus freight of $AUD36 while most of the local retailers had them priced around $AUD585. A little investigation on the "Product Review' website revealed that although camerasky had an Australian address they were actually sourcing and mailing their goods from Hong Kong and the official Nikon warranty on their cameras was therefore not applicable in Australia. It was also suggested that some of these cameras may have been Chinese knock-offs rather than the real thing. They offered their own warranty at a price but I did not want to have to deal with people in Hong Kong if things did go wrong and there were some pretty sad stories on the Product Review website along those lines.
I don't suggest that Walmart is dodgy but if they are anything like the bigger chain stores in Australia you may well find that while they are good at selling stuff they are less than useful if you need parts, advice or any kind or after-sales service.
I bought my Nikon from a specialist camera store here in Perth. It has the official Nikon warranty duly registered and if anything goes wrong competent help is only a 20 minute drive away. I like that